a)
√(x+1)=x-5
x+1= (x-5)²
x+1=x²-10x+25
x²-11x+24=0
(x-3)(x-8)=0
(x-3)=0 ⇒ x=3
(x-8)=0 ⇒ x=8
b)√(x-1)-x = - 7
√(x-1) = x - 7
x-1 = (x - 7)²
x-1 = x² -14x+49
x²-15x+50=0
(x-5)(x-10)=0
(x-5)=0 x=5
(x-10)=0 x=10
e)√(17+2x-3x²) = x+1
17+2x-3x²=(x+1)²
17+2x-3x²=x²+2x+1
4x²=16
x²=4
x=√4 ⇒ x=2 x=-2
