Bonjour
(a + b)^2 = a^2 + 2ab + b^2
Développe puis réduis ces expressions:
E=(x+1)^2+7x(2-x)
E = x^2 + 2x + 1 + 7x * 2 - 7x * x
E = x^2 + 2x + 1 + 14x - 7x^2
E = x^2 - 7x^2 + 2x + 14x + 1
E = -6x^2 + 16x + 1
F=(x+3)(2x-1)-3x(2x+5)
F = x * 2x - x * 1 + 3 * 2x - 3 * 1 - 3x * 2x - 3x * 5
F = 2x^2 - x + 6x - 3 - 6x^2 - 15x
F = 2x^2 - 6x^2 + 6x - x - 15x - 3
F = -4x^2 - 10x - 3
