<span>(x-4)(x+4)+(3x-1)²=x</span>²-16+9x²-6x+1=10x²-6x-15
X² + 3x + 2 = 0
D = 3² - 4 × 1 × 2 = 9 - 8 = 1, D>0
x1 = -3 + 1 / 2 × 1 = -3 + 1 / 2 = -1.
x2 = -3 - 1 / 2 × 1 = -4 / 2 = -2.
x1 = -1, x2 = -2.
Х=у+1
Х^2+у^2+2ху=9
(У+1)^2+у^2+2(у+1)у=9
У^2+2у+1+у^2+2у^2+2у=9
4у^2+4у=8
4у(у+1)=8
4у=8 у=2
У+1=8 у=7
Х=2+1=3
Х=7+1=8