Question

Write -2x2-12x-8 in the form a(x+b)2+c, where a, b and c are numbers. What are the values of a, b and c? Hence, write down the coordinates of the turning point of the curve y= -2x2-12x-8

Answer 1

-2(x + 3)^2 + 10

(-3, 10).

Explanation:

-2x2-12x-8

Dividing through by -2:

= -2(x^2 + 6x + 4)

= -2[x + 3)^2 - 9 + 4)

= 2[x + 3)^2 - 5)

= -2(x + 3)^2 + 10

The coordinates of the turning point

= (-3, 10).