x-10 = root 9x |
Square both sides |
(x-10)squared = 9x |
Expand |
(X-10) (x-10) = 9x |
xsquared -10x -10x +100 =9x |
Simplify |
x squared -20x + 100 = 9x |
-9x from both sides |
X squared -29x +100 = 0 |
Factorise |
(x - 25) (x - 4) = 0 |
x = 25 or x = 4