Question

why is it 4 and not -4 ? (attached)

Answer 1

c=4 because
x^2-9=8x-25 when x=4

Answer 2

If x was -4, you would have x^2 - 9 = 16-9 = 5
But 8x-25 = 8(-4) - 25 = 57
So they aren't equal at that point.

Answer 3

\[c^{2}-9 = 8c -25\]\[c^{2} - 8c +16 = (c-4)^{2}\]
sorry.. forgot i have to invert the root that i find in the parethesis

Answer 4

Err 16-9 =7

Answer 5

c^2-9-8c+25=0
c^2-8c+16=0
(c-4)^2=0 oh thats what you have nvm

Answer 6

yup but thanks hehe