tolong bantu plisss besok di kumpul

1)4x+8 = x+17
4x-x = 17 - 8
3x = 9
x=9÷3
x=3

2) 6x-3=7x+2
6x-7x=2+3
-x = 5
x=5

3) (x+9)(2x+y)= 2x²+xy+18x+9y

4) (x-y) ²=x²-xy-xy-y²
=x²-y²-2xy