Question

Write the quadratic equation whose roots are 2 and -1, and whose leading coefficient is 1

Answer 1

y² - y - 2

Explanation:

Quadratic functions can be solved using the roots. To solve for roots, we set the two factors equal to zero and solve for the variable. So, we are going to reverse that here.

y + 2 = 0

y = -2

y - 1 = 0

y = 1

Then, we know our factors are (y - 2) and (y + 1), so we just FOIL these.

(y - 2)(y + 1)

y² + 1y - 2y - 2

y² - y - 2

This would be our final equation.