1. Evaluate the expression $$\frac{11}{22}x^{-22} + \frac{11}{33}x^{-33} + \frac{11}{22}x^{-44}$$ for given options.
Step 1: Simplify each term.
$$\frac{11}{22} = \frac{1}{2}, \quad \frac{11}{33} = \frac{1}{3}$$
Step 2: Expression becomes:
$$\frac{1}{2}x^{-22} + \frac{1}{3}x^{-33} + \frac{1}{2}x^{-44}$$
Step 3: Without a specific value for $x$, we cannot simplify further. Assuming $x=1$, sum is:
$$\frac{1}{2} + \frac{1}{3} + \frac{1}{2} = \frac{1}{2} + \frac{1}{2} + \frac{1}{3} = 1 + \frac{1}{3} = \frac{4}{3}$$
None of the options match this, so more context is needed.
2. Convert 0.000000078 to standard form.
Step 1: Count decimal places to move decimal point right to get a number between 1 and 10.
$$0.000000078 = 7.8 \times 10^{-8}$$
Answer: (a) 7.8× 10^{-8}
3. Find multiplicative inverse of $$\frac{77}{99}x^{-33}$$.
Step 1: Multiplicative inverse is reciprocal:
$$\left(\frac{77}{99}x^{-33}\right)^{-1} = \frac{99}{77}x^{33}$$
Answer: (c) $$\frac{99}{77}x^{33}$$
4. Assertion: $$2^{-3} = \frac{1}{2^3}$$ is true.
Reason: Negative exponent means reciprocal of base raised to positive exponent, also true.
Reason correctly explains Assertion.
Answer: (a)
5. Assertion: Multiplicative inverse of 10^5 is 10^{-5} is false.
Reason: Multiplicative inverse of a number multiplied by original number gives 1 is true.
Answer: (d)
6. Evaluate $$(5^{-1} \times 2^{-1}) \times 6^{-1}$$.
Step 1: Write as reciprocals:
$$\frac{1}{5} \times \frac{1}{2} \times \frac{1}{6} = \frac{1}{60}$$
7. Express in standard form:
a) 0.00001275 m = $$1.275 \times 10^{-5}$$ m
b) 0.00000000000000000016 coulomb = $$1.6 \times 10^{-19}$$ coulomb
8. Find $m$ such that:
$$( -3 )^{m(m+1)} \times ( -3 )^{5} = ( -3 )^{7}$$
Step 1: Add exponents:
$$m(m+1) + 5 = 7$$
Step 2: Solve quadratic:
$$m^2 + m + 5 = 7 \Rightarrow m^2 + m - 2 = 0$$
Step 3: Factor:
$$(m+2)(m-1) = 0 \Rightarrow m = -2 \text{ or } 1$$
9. Population ratio:
$$\frac{1.8 \times 10^{6}}{9 \times 10^{3}} = \frac{1.8}{9} \times 10^{6-3} = 0.2 \times 10^{3} = 200$$
Population in 2010 is 200 times that in 2012.
10. Total viewers:
$$8.5 \times 10^{6} + 1.15 \times 10^{6} = (8.5 + 1.15) \times 10^{6} = 9.65 \times 10^{6}$$
11. Simplify and write in positive exponents:
a) $$\frac{2^{x} x^{-3}}{x^{-8} x^{4}} = 2^{x} x^{-3 - (-8) - 4} = 2^{x} x^{1} = 2^{x} x$$
b) $$6^{m} m^{5} \times 3^{m} m^{-8} = (6 \times 3)^{m} m^{5 - 8} = 18^{m} m^{-3}$$
c) $$\frac{x^{x} x^{8}}{x^{3} 4} = \frac{x^{x+8}}{4 x^{3}} = \frac{x^{x+5}}{4}$$
d) $$-3^{4} x^{x} x^{-1} = -81 x^{x-1}$$
e) $$x^{x^{6}} x^{x^{4}} = x^{x^{6} + x^{4}}$$
12. Simplify:
$$\frac{25 \times t^{t^{-4}}}{5^{-3} \times 125 \times t^{t^{-8}}}$$
Step 1: Simplify constants:
$$25 = 5^{2}, \quad 125 = 5^{3}, \quad 5^{-3} = \frac{1}{5^{3}}$$
Step 2: Substitute:
$$\frac{5^{2} t^{t^{-4}}}{\frac{1}{5^{3}} \times 5^{3} t^{t^{-8}}} = \frac{5^{2} t^{t^{-4}}}{t^{t^{-8}}} = 5^{2} t^{t^{-4} - t^{-8}}$$
Case Study:
a) Distance of Mercury from Sun in standard form:
$$5.79 \times 10^{7} \text{ km}$$
b) Sum of distances of Mercury and Venus:
$$5.79 \times 10^{7} + 1.082 \times 10^{8} = 1.661 \times 10^{8} \text{ km}$$
c) Difference of distances of Earth and Venus:
$$1.496 \times 10^{8} - 1.082 \times 10^{8} = 4.14 \times 10^{7} \text{ km}$$
Exponents Standard Form
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