Bonjour,
Ex62
a. 5 * y + 3 * y = (5 + 3) * y = 8 * y= 8y
b. x + 4 *x + 3 = 5 * x + 3 = 5x + 3
c. 7x + 21 = 7 * x + 7 * 3 = 7 * ( x + 3) = 7 (x + 3)
d. x * x * 4 - x * 6 + 2 = 4x² - 6x + 2
Ex63
a. 8 + 2 * (x - 3) = 8 + 2 * x - 2 * 3 = 8 + 2x - 6 = 2x + 8 - 6 = 2x + 2
b. 5x (2x - 6) = 5x * 2x - 5x * 6 = 10x² - 30x
c. (-4 - 3x) * 2 = -4 * 2 - 3x * 2 = -8 - 6x = -6x - 8
d. -3 (4 - x²) = -3 * 4 -3 * (-x²) = -12 + 3x² = 3x² - 12
e. 10x - 3 (4x - 7) + 9 = 10x - 12x + 21 + 9 = -2x + 30
f. (4x² - 3) * 2 + 4x = 8x² - 6 + 4x = 8x² + 4x - 6
