MATH SOLVE

4 months ago

Q:
# Solve −2x2 − 16x − 44 = 0. x equals negative 8 plus or minus I square root of 6 x equals negative 8 plus or minus 2i square root of 6 x equals negative 4 plus or minus i square root of 6 x equals negative 4 plus or minus 2i square root of 6

Accepted Solution

A:

I would immediately reduce this by div. every term by -2:

x^2 + 8x + 22 = 0

Next, I'd "complete the square:"

x^2 + 8x + (4)^2 - (4)^2 + 22 = 0

(x + 4)^2 - 16 + 22 = 0, so that (x+4)^2 + 4 = 0.

Then sqrt( (x+4)^2 = sqrt(-4)

x+4 = plus or minus i*2

x = -4 plus or minus i*2 (answer)

x^2 + 8x + 22 = 0

Next, I'd "complete the square:"

x^2 + 8x + (4)^2 - (4)^2 + 22 = 0

(x + 4)^2 - 16 + 22 = 0, so that (x+4)^2 + 4 = 0.

Then sqrt( (x+4)^2 = sqrt(-4)

x+4 = plus or minus i*2

x = -4 plus or minus i*2 (answer)