Finding x?

Question

3(x-4)^2-72=0

Answer 1

3(x-4)² - 72 = 0
3(x-4)² = 72
(x-4)² = 24
x - 4 = ±√24 = ±2√6
x = 4 ± 2√6

Answer 2

Square the x-4, (x^2+16), then multiply it by 3, (3x^2+48-72), combine like terms, (3x^2-24=0) now, add 24 to both sides, (3x^2=24), divide by 3 (x^2=8) and you have the square root of 8=x

Answer 3

you could also use the quadratic formula...
[-b +/- root(b^2-4ac)]/2a

what do you plug in?

expand the question... and get
3x^2 - 24x +48 -72=0
3x^2 - 24x - 24= 0

(a=3, b= -24, c= -24)

the answer turns out to be the same thing

Answer 4

3(x-4)² - 72 = 0
3(x² - 8x + 16) - 72 = 0
3x² - 24x + 48 -72 = 0
3x² - 24x - 24 = 0
x² - 8x - 8 =0
for
ax² + bx + c = 0
x = (-b ±√(b² - 4ac)) / 2a
x = (8 ±√(64 - 4*1*-8)) / 2
x = (8 ±√96) / 2
x = ( 8 ± 4√6) /2
x = 4 ± 2√6
x = 8.9 or x = -0.9