Solve the quadratic equation by completing the square. Verify your answer graphically. (Enter your answers as a comma-separated list.)

Question

16x2 − 24x − 23 = 0

my answer was:
x =16(x−3/4)^2−32

but online website (where i do my assignments that is posted by my teacher), says it is wrong, i just don't understand why.

Answer 1

You've completed the square correctly, but the left side of your equation should be 0, not x.
0 =16(x−3/4)^2−32.
Also, there's more work to do. Rearrange the equation to isolate x. This will take about 4 steps.

Answer 2

16 ( x − 3 / 4 )² − 32 = 0

Divide both sides by 16

( x − 3 / 4 )² − 2 = 0

Add 2 to both sides

( x − 3 / 4 )² − 2 + 2 = 0 + 2

( x − 3 / 4 )² = 2

Take the square root of both sides

x − 3 / 4 = ± √2

Add 3 / 4 to both sides

x − 3 / 4 + 3 / 4 = ± √2 + 3 / 4

x = 3 / 4 ± √2

The solutions are:

x = 3 / 4 - √2 and x = 3 / 4 + √2

Answer 3

Thanks Bosnian