Question

X-6=square root -7x+72 sorry no radical symbol on iPad

Answer 1

\[x-6=\sqrt{-7x+72}\]

Answer 2

Square the whole equation and get a quadratic

Answer 3

x - 6 = sqrt(-7x + 72)
Square both sides
(x-6)^2 = [ sqrt(-7x + 72) ] 2
(x-6)^2 = -7x + 72
x^2 - 12x + 36 = -7x + 72
x^2 -5x - 36 = 0
(x - 9) ( x + 4) = 0
x = 9 or x = -4
x = 9
Note: x = -4 is discarded because the principal square root of an expression is never equal to a negative. If x were -4, then x - 6 = sqrt(-7x + 72) would begin as -4 -6 = sqrt(....) which cannot happen in the set of Real numbers.