1. Problem: Find three consecutive integers where 5 times the sum of the first two is 7 more than the opposite of the third.
Let the integers be $x$, $x+1$, $x+2$.
Equation: $5(x + (x+1)) = -(x+2) + 7$
Simplify: $5(2x+1) = -x - 2 + 7$
$10x + 5 = -x + 5$
Add $x$ to both sides: $10x + x + 5 = 5$
$11x + 5 = 5$
Subtract 5: $11x = 0$
$x = 0$
Integers: $0, 1, 2$
2. Problem: Find four consecutive even integers where 3 times the sum of the first two is 18 more than 5 times the third.
Let the integers be $x$, $x+2$, $x+4$, $x+6$.
Equation: $3(x + x+2) = 5(x+4) + 18$
Simplify: $3(2x+2) = 5x + 20 + 18$
$6x + 6 = 5x + 38$
Subtract $5x$: $x + 6 = 38$
$x = 32$
Integers: $32, 34, 36, 38$
3. Problem: Price reduced by 4% to sell for 3440. Find original price and reduction.
Let original price be $P$.
Equation: $P - 0.04P = 3440$
$0.96P = 3440$
$P = \frac{3440}{0.96} = 3583.33$
Reduction: $3583.33 - 3440 = 143.33$
4. Problem: Flood tide rise increased inundated land by 270%. Former inundation 1400 acres.
Increase: $270\% = 2.7$ times original.
New inundation: $1400 + 2.7 \times 1400 = 1400 + 3780 = 5180$ acres.
5. Problem: Ezekiel has 7452 jeroboams, 1.62 times the next country.
Let next country have $x$ jeroboams.
$1.62x = 7452$
$x = \frac{7452}{1.62} = 4600$
6. Problem: $\frac{7\sqrt{2}}{3}$ belongs to which sets?
Answer: Rational multiples of irrational numbers, so it belongs to the set of real numbers and irrational numbers.
7. Simplify: $-2(4 - 1)(-1 - 2^0) + |-3 + 5|$
Calculate powers: $2^0 = 1$
Expression: $-2(3)(-1 - 1) + |2| = -2(3)(-2) + 2 = 12 + 2 = 14$
8. What fraction of $2 \frac{1}{4}$ is $7 \frac{3}{8}$?
Convert to improper fractions: $2 \frac{1}{4} = \frac{9}{4}$, $7 \frac{3}{8} = \frac{59}{8}$
Fraction: $\frac{59/8}{9/4} = \frac{59}{8} \times \frac{4}{9} = \frac{236}{72} = \frac{59}{18}$
9. Solve: $2.2x - 0.1x + 0.02x = -2 - 0.32x$
Combine like terms: $2.12x = -2 - 0.32x$
Add $0.32x$: $2.44x = -2$
$x = \frac{-2}{2.44} = -0.82$
10. Evaluate: $\frac{\sqrt[3]{x} + 7}{3}$ if $x = -50$
Calculate cube root: $\sqrt[3]{-50} = -3.684$
Expression: $\frac{-3.684 + 7}{3} = \frac{3.316}{3} = 1.105$
11. Find equations of lines (bottom-left grid):
Line 1 passes through (0,1) and (2,3): slope $m = \frac{3-1}{2-0} = 1$
Equation: $y = x + 1$
Line 2 passes through (0,3) and (2,1): slope $m = \frac{1-3}{2-0} = -1$
Equation: $y = -x + 3$
12. Find equations of lines (bottom-left grid):
Line 1 passes through (0,0) and (3,3): slope $m=1$
Equation: $y = x$
Line 2 passes through (0,3) and (3,0): slope $m = -1$
Equation: $y = -x + 3$
14. Simplify:
$$\frac{(0.0056 \times 10^{-3})(100000 \times 10^{-14})}{8000 \times 10^{15}}$$
Calculate numerator: $0.0056 \times 10^{-3} = 5.6 \times 10^{-6}$
$100000 \times 10^{-14} = 10^5 \times 10^{-14} = 10^{-9}$
Numerator: $5.6 \times 10^{-6} \times 10^{-9} = 5.6 \times 10^{-15}$
Denominator: $8000 \times 10^{15} = 8 \times 10^3 \times 10^{15} = 8 \times 10^{18}$
Fraction: $\frac{5.6 \times 10^{-15}}{8 \times 10^{18}} = 0.7 \times 10^{-33} = 7 \times 10^{-34}$
15. Simplify: $\frac{x^2 + y}{a - \frac{x}{y}}$
Rewrite denominator: $a - \frac{x}{y} = \frac{ay - x}{y}$
Expression: $\frac{x^2 + y}{\frac{ay - x}{y}} = (x^2 + y) \times \frac{y}{ay - x} = \frac{y(x^2 + y)}{ay - x}$
16. Add: $\frac{4}{x + y} + \frac{6}{x} - \frac{4}{ax}$
Common denominator: $a x (x + y)$
Rewrite terms:
$\frac{4 a x}{a x (x + y)} + \frac{6 a (x + y)}{a x (x + y)} - \frac{4 (x + y)}{a x (x + y)}$
Sum numerator: $4 a x + 6 a (x + y) - 4 (x + y)$
Final: $\frac{4 a x + 6 a (x + y) - 4 (x + y)}{a x (x + y)}$
17. Expand: $\frac{x^2 a}{y^2} \cdot \left( \frac{a^4 y^{-2}}{x} - \frac{3 x^2 a}{y^2} \right)$
Distribute:
$\frac{x^2 a}{y^2} \cdot \frac{a^4 y^{-2}}{x} = \frac{x^2 a a^4 y^{-2}}{y^2 x} = \frac{x a^5 y^{-2}}{y^2} = x a^5 y^{-4}$
$\frac{x^2 a}{y^2} \cdot \left(- \frac{3 x^2 a}{y^2} \right) = - \frac{3 x^4 a^2}{y^4}$
Sum: $x a^5 y^{-4} - 3 x^4 a^2 y^{-4} = y^{-4} (x a^5 - 3 x^4 a^2)$
18. Simplify by adding like terms:
$a^2 x y - 3 a^2 x / y^{-1} + 4 x / (y^{-1} a^2) + 5 x^{-1} y / a^2$
Rewrite powers:
$-3 a^2 x / y^{-1} = -3 a^2 x y$
$4 x / (y^{-1} a^2) = 4 x y / a^2$
$5 x^{-1} y / a^2 = 5 y / (a^2 x)$
Group terms:
$a^2 x y - 3 a^2 x y = -2 a^2 x y$
Final: $-2 a^2 x y + 4 x y / a^2 + 5 y / (a^2 x)$
19. Solve by graphing:
$y = x + 4$
$y = -x + 2$
Set equal: $x + 4 = -x + 2$
$2x = -2$
$x = -1$
$y = -1 + 4 = 3$
Solution: $(-1, 3)$
20. Use substitution:
$5N_M + 10N_D = 450$
$N_D = N_N + 30$
Substitute $N_D$: $5N_M + 10(N_N + 30) = 450$
$5N_M + 10N_N + 300 = 450$
$5N_M + 10N_N = 150$
No value for $N_M$ or $N_N$ given, solution in terms of variables.
21. Use elimination:
$5x - 2y = 7$
$4x + y = 3$
Multiply second by 2: $8x + 2y = 6$
Add to first: $5x - 2y + 8x + 2y = 7 + 6$
$13x = 13$
$x = 1$
Substitute: $4(1) + y = 3$
$y = -1$
Solution: $(1, -1)$
22. Solve: $\frac{p}{4} - \frac{p+2}{6} = -4$
Common denominator 12:
$3p - 2(p+2) = -48$
$3p - 2p - 4 = -48$
$p - 4 = -48$
$p = -44$
23. Solve: $k + \frac{2}{5} - \frac{k}{10} = \frac{3}{20}$
Multiply all by 20:
$20k + 8 - 2k = 3$
$18k + 8 = 3$
$18k = -5$
$k = -\frac{5}{18}$
24. Simplify: $3\sqrt{72} - 14\sqrt{18} + 6\sqrt{8}$
Simplify radicals:
$\sqrt{72} = 6\sqrt{2}$
$\sqrt{18} = 3\sqrt{2}$
$\sqrt{8} = 2\sqrt{2}$
Expression: $3(6\sqrt{2}) - 14(3\sqrt{2}) + 6(2\sqrt{2}) = 18\sqrt{2} - 42\sqrt{2} + 12\sqrt{2} = (18 - 42 + 12)\sqrt{2} = -12\sqrt{2}$
25. Given: $R_T T_T = R_B T_B$, $R_T = 80$, $R_B = 20$, $T_B = T_T + 18$
Equation: $80 T_T = 20 (T_T + 18)$
$80 T_T = 20 T_T + 360$
$60 T_T = 360$
$T_T = 6$
$T_B = 6 + 18 = 24$
26. Given: $R_L T_L = R_S T_S$, $R_L = 120$, $R_S = 280$, $T_S = 20 - T_L$
Equation: $120 T_L = 280 (20 - T_L)$
$120 T_L = 5600 - 280 T_L$
$400 T_L = 5600$
$T_L = 14$
$T_S = 20 - 14 = 6$
27. Factor: $4x^2 + 40x + 100$
Common factor 4:
$4(x^2 + 10x + 25)$
Factor quadratic:
$4(x + 5)^2$
28. Factor: $-x^3 - 30x - 11x^2$
Rewrite: $-x^3 - 11x^2 - 30x$
Common factor $-x$:
$-x(x^2 + 11x + 30)$
Factor quadratic:
$-x(x + 5)(x + 6)$
29. Factor: $ax^2 - 35a + 2ax$
Common factor $a$:
$a(x^2 - 35 + 2x)$
Rewrite quadratic:
$a(x^2 + 2x - 35)$
Factor quadratic:
$a(x + 7)(x - 5)$
Problem Set 85 3E46B9
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