Bonjour,
-2/3 + 5/7 = -14/21 + 15/21 = 1/21
2 × (-1/5) = -2/5
(-1/3)/(6/9) = (-1/3)×(9/6) = -9/18 = -1/2
(2x-1)(3-x) = 6x-2x²-3+x = -2x²+7x-3
4(x/3 + 3)-2(1 - 4/5) = 4x/3 + 12 - 2 + 8/5 = 4x/3 + 10 - 8/5 = 4x/3 + 116/10
= 4x/3 + 58/5
14x²-21x = 7x(2x-3)
18x-9x²+27x³ = 9x(2-x+3x²)
