X - y = 7
Xy = - 10
••••••••••
y = x - 7
X( x - 7 ) = - 10
X^2 - 7x + 10 = 0
D = 49 - 40 = 9 = 3^2
X1 = ( 7 + 3 ) : 2 = 5
X2 = ( 7 - 3 ) : 2 = 2
y1 = 5 - 7 = - 2
y2 = 2 - 7 = - 5
Ответ ( 5 ; - 2 ) ; ( 2 ; - 5 )
2x²-5x-6=3-2x
2x²-5x+2x-6-3=0
2x²-3x-9=0
D=9+72=81
x=3±9/4
x=3
x=-1,5
А) (4–y+1)(4+y+1)=(3–y)(5+y)
б) 1/27a^3–x^3=(1/3a–x)(1/9a^2+1/3ax
+x^2)
в) (a^2–4b^2)(a^2+4b^2)=(a–2b)(a+2b)(a^2+4b^2)
г) 3(c–a)–(c^2–a^2)=3(c–a)–(c–a)(c+a)=(c–a)(3–c–a)
Вродебы так
8х-(2х+4)=2*(3х-2)
8х-2х-4=6х-4
8х-2х-6х=-4+4
0=0