a) -x² + 7x = 0x(-x + 7) = 0x = 0 or x = 7
b) 19x - x² = 0x(19 - x) = 0x = 0 or x = 19
c) x² - 100 = 0(x + 10)(x - 10) = 0x = -10 or x = 10
a) -x² + 7x = 0
x(-x + 7) = 0
x = 0 or x = 7
b) 19x - x² = 0
x(19 - x) = 0
x = 0 or x = 19
c) x² - 100 = 0
(x + 10)(x - 10) = 0
x = -10 or x = 10