1.
(x-4)²-(x+9)²=195
x²-8x+16-(x²+18x+81)=195
x²-8x+16-x²-18x-81=195
-26x=195-16+81
-26x=260
x=-10
Ответ x=-10.
________________________________________________
2.
x+7x²-y-7y²=(x-y)+7(x²-y²)=(x-y)+7(x-y)(x+y)=(x-y)(1+7x+7y)
Ответ: (x-y)(7x+7y+1).
4(x+1)-6(2-x)>2,
4x + 4 - 12 + 6x > 2,
10x - 8 > 2,
10x > 2 + 8,
10x > 10,
x > 10:10,
x > 1.
Ответ: x>1.
(3x-2)*(7x+4)=0
3х-2=0
7х+4=0
х=2/3
х=-4/7
х1=-4/7
х2=2/3
Лупа ,- зеркало , оправа , ручка
11х -1+1-7х= 3х = 3*4 =12