Expand and put them all on one side in decreasing order of degree of x: x^2 - 9x - 10 = 0 -9 = 1 - 10 -10 = 1 * (-10) so (x+1)(x-10) = 0 So x+1=0 (x= -1) And x-10=0 (x=10) So the solutions are 10 and -1 which is d.
x( x - 9) = 10 x² - 9x = 10 x² - 9x - 10 = 0 Factor left side (x +1)(x-10) Now we can set the factors equal to 0 x +1 = 0 or x - 10 = 0 x = 0 - 1 or x = 0 + 10 x= - 1 or x = 10
