Answer:
f (x) = -2 (x + 6)^2 + 2
Step-by-step explanation:
f (x) = -2x^2 - 24x - 70 <--- divide out -2 out of the first two terms...
f (x) = -2 (x^2 + 12x) - 70 <-- divide the x coefficient by 2 and then square it, then add AND subtract it)
f (x) = -2 (x^2 + 12x + (12/2)^2 - (12/2)^2) - 70
f (x) = -2 (x^2 + 12x + 36 - 36) - 70 <--- distribute the -2 onto -36 to get it out of the brackets..
f (x) = -2 (x^2 + 12x + 36) + 72 - 70 <-- combine constants and factor perfect square trinomial...
f (x) = -2 (x + 6)^2 + 2 <-- standard form...
