Sagot :
a) 3(2x - 6 ) - (3 - 5x) = 6x - 18 - 3 + 5x = 11x -21
b) (5- 2y) - (-3y + 7) = 5 - 2y + 3y - 7 = y - 2
c) 4(6 + z) + (z - 3) (2 - z) = 24 + 4z + 2z - z² - 6 + 3z = -z² + 9z + 18
d) (2t - 5) (3t +2) - (t² + 6) = 6t² + 4t - 15t - 10 - t² - 6 = 5t² -11t - 16
voilà :)
a) 3(2x - 6) - (3 - 5x)
= 6x - 18 - 3 + 5x
= 11x - 21
b) (5 - 2y) - (- 3y + 7)
= 5 - 2y +3y - 7
= y - 2
c) 4(6 + z) + (z - 3)(2 - z)
=24 + 4z + 2z - z² - 6 + 3z
= 18 + 9z - z²
d) (2t - 5)(3t + 2) - (t² + 6)
= 6t² +4t - 15t - 10 -t² - 6
= 5t² - 9t - 16