1. **State the problem:**
Solve the simultaneous equations:
$$x - 6y = 10$$
$$3y^2 = 4x + 7$$
2. **Show that** $3y^2 - 24y - 47 = 0$:
From the first equation, express $x$ in terms of $y$:
$$x = 6y + 10$$
Substitute into the second equation:
$$3y^2 = 4(6y + 10) + 7$$
$$3y^2 = 24y + 40 + 7$$
$$3y^2 = 24y + 47$$
Bring all terms to one side:
$$3y^2 - 24y - 47 = 0$$
3. **Solve the quadratic equation** $3y^2 - 24y - 47 = 0$:
Use the quadratic formula:
$$y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
where $a=3$, $b=-24$, $c=-47$.
Calculate the discriminant:
$$\Delta = (-24)^2 - 4 \times 3 \times (-47) = 576 + 564 = 1140$$
Calculate the roots:
$$y = \frac{24 \pm \sqrt{1140}}{6}$$
Approximate $\sqrt{1140} \approx 33.76$:
$$y_1 = \frac{24 + 33.76}{6} = \frac{57.76}{6} = 9.6$$
$$y_2 = \frac{24 - 33.76}{6} = \frac{-9.76}{6} = -1.6$$
4. **Find corresponding $x$ values** using $x = 6y + 10$:
For $y=9.6$:
$$x = 6 \times 9.6 + 10 = 57.6 + 10 = 67.6$$
For $y=-1.6$:
$$x = 6 \times (-1.6) + 10 = -9.6 + 10 = 0.4$$
5. **Final answers to 1 decimal place:**
$$(x,y) = (67.6, 9.6) \text{ or } (0.4, -1.6)$$
Simultaneous Equations 5Ad166
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