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a) 10+√(x+2) = x
√(x+2) = x-10
[√(x+2)]² = (x-10)²
x+2 = x²-20x+100
x²-21x+98 = 0
Δ = 49
x' = 21+7/2 = 28/2 = 14
x'' = 21-7/2 = 14/2 = 7
S{7;14}
b) √(26+x) - √(26-x) = 2
[√(26+x) -√(26-x)]² = 2²
(26+x)-2[√(26+x)(√(26-x)]+(26-x) = 2
-2[√(26+x)(√(26-x)] = 2-52
(-2[√(26+x)(√(26-x)])² = (-50)²
4(26+x)(26-x) = 2500
676-26x+26x-x² = 2500/4
676-x² = 625
x² = 676-625
x² = 51
x = +√51
ou
x = -√51
√(x+2) = x-10
[√(x+2)]² = (x-10)²
x+2 = x²-20x+100
x²-21x+98 = 0
Δ = 49
x' = 21+7/2 = 28/2 = 14
x'' = 21-7/2 = 14/2 = 7
S{7;14}
b) √(26+x) - √(26-x) = 2
[√(26+x) -√(26-x)]² = 2²
(26+x)-2[√(26+x)(√(26-x)]+(26-x) = 2
-2[√(26+x)(√(26-x)] = 2-52
(-2[√(26+x)(√(26-x)])² = (-50)²
4(26+x)(26-x) = 2500
676-26x+26x-x² = 2500/4
676-x² = 625
x² = 676-625
x² = 51
x = +√51
ou
x = -√51
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