Besoin d'aide, je n'arrive pas

1)
J = (x + 3) + 2x - 7 + (3x - 7x² + 6)
J = x + 3 + 2x - 7 + 3x - 7x² + 6
J = - 7x² + x + 2x + 3x + 3 + 6 - 7
J = - 7x² + 6x + 2

2) Pour x = 1
a)
J = (x + 3) + 2x - 7 + (3x - 7x² + 6)
J = (1 + 3) + 2 * 1 - 7 + (3 * 1 - 7 * 1² + 6)
J = 1 + 3 + 2 - 7 + 3 - 7 * 1 + 6
J = 1 + 3 + 2 - 7 + 3 - 7 + 6
J = 1 + 3 + 2 + 3 + 6 - 7 - 7
J = 16 - 14
J = 2

b)
J = - 7x² + 6x + 2
J = - 7 * 1² + 6 * 1 + 2
J = - 7 + 7 + 2
J = - 7 + 9
J = 2

1) J= -x-3+2x-7+3x-7x^2+6
= -7x^2+4x-4
2-a) J(1)= -(1+3)+2(1)-7+[ 3(1)-7(1)^2+6]
= -1-3+2-7+3-7+6
= -7
b) -7(1)^2+4(1)-4
= -7+4-4
= -7