[tex]x+7 = \sqrt{(5-x)(3x+11)} [/tex]
Ridici ecuatia la puterea a doua si o sa obtii:
[tex](x+7)^{2} = (5-x)(3x+11)[/tex]
[tex]x^{2}+14x+49 = 15x+55-3x^{2}-11x [/tex]
[tex]x^{2}+14x+49 = 4x+55-3x^{2} [/tex]
[tex]4x^{2}+10x-6 = 0 [/tex]
Δ = 100+96 = 196
[tex] x_{1} [/tex] = (-10+√196)/8 = (-10+14)/8 = 4/8 = 1/2
[tex] x_{2} [/tex] = (-10-√196)/8 = (-10-14)/8 = (-24)/8 = -3
