Question

The roots of the quadratic equation $x^2$+5x-14=0 is

• A. 2, -7
• B. -2,-7
• C. -2,7
• D. 2,7

Answer 1

The correct option is A

2, -7

$x^2$+5x-14=0

We need to split the coefficient of x such that the sum of the factors is 5 and their product is -14.

So we will find the coefficient as 7 and -2.

The sum of 7 and -2 is 5 and product is -14.

So now re-write the equation

$x^2$+7x-2x-14=0

Taking common terms out

x(x+7)-2(x+7)=0

Again taking out the common terms

(x-2)(x+7)=0

Now equate the factors to zero to find the roots.

So the roots of the equation are 2,-7