Question

If $y=a{x}^2+7x-15$ makes an intercept of $1\frac{1}{2}$ units on X-axis, then the value of $a$ is?

• A. $7$
• B. $-15$
• C. $2$
• D. $-8$

Answer 1

The correct option is C $2$

The curve makes an intercept of $1\frac{1}{2}=\frac{3}{2}$ units on the X-axis.

So $(\frac{3}{2},0)$ is a point on the curve.

$\therefore 0=a{\left(\frac{3}{2}\right)}^2+7\left(\frac{3}{2}\right)-15$

$\therefore a=2$

So, the answer is option (C).