Bonjour,
Ex. 1 :
1) 3x² - (5x + 4) + (1 - 7x²) = 3x² - 7x² -5x - 4 + 1 = -4x² - 5x - 3
2) (4x - 2)(3 - 6x) + 5x(8 + x) = 12x -24x² - 6 + 12x + 40x + 5x² = -19x² + 64x - 6
3) 3(2²) + 10(2) - 9 = 12 + 20 - 9 = 23
4) -2/11 × (4/7 + 3/14) = -2/11 × (8/14 + 3/14)
= -2/11 × 11/14
= -2/14
= -1/7
