Question

(2u^2-3u+9)-(4u^2-5u-8)+(-6u^2+4u-9)

Answer 1

u = 3/8 + sqrt(73)/8 or u = 3/8 - sqrt(73)/8

Explanation:

Solve for u over the real numbers:

-8 u^2 + 6 u + 8 = 0

Divide both sides by -8:

u^2 - (3 u)/4 - 1 = 0

Add 1 to both sides:

u^2 - (3 u)/4 = 1

Add 9/64 to both sides:

u^2 - (3 u)/4 + 9/64 = 73/64

Write the left hand side as a square:

(u - 3/8)^2 = 73/64

Take the square root of both sides:

u - 3/8 = sqrt(73)/8 or u - 3/8 = -sqrt(73)/8

Add 3/8 to both sides:

u = 3/8 + sqrt(73)/8 or u - 3/8 = -sqrt(73)/8

Add 3/8 to both sides:

Answer: u = 3/8 + sqrt(73)/8 or u = 3/8 - sqrt(73)/8