#5**+1 **

x * (4x + 7) =480, solve for x

Solve for x:

x (4 x + 7) = 480

Expand out terms of the left hand side:

4 x^2 + 7 x = 480

Divide both sides by 4:

x^2 + (7 x)/4 = 120

Add 49/64 to both sides:

x^2 + (7 x)/4 + 49/64 = 7729/64

Write the left hand side as a square:

(x + 7/8)^2 = 7729/64

Take the square root of both sides:

x + 7/8 = sqrt(7729)/8 or x + 7/8 = -sqrt(7729)/8

Subtract 7/8 from both sides:

x = sqrt(7729)/8 - 7/8 or x + 7/8 = -sqrt(7729)/8

Subtract 7/8 from both sides:

**Answer: | x = sqrt(7729)/8 - 7/8 =~10.11 inches.**

Guest Apr 18, 2017

#6**+1 **

I think you are just a.) cheating on a test b.) cheating in your homework c.) cheating...period.

wgunningham
Apr 18, 2017