Explicație pas cu pas:
a) 9(x-7)=-63
9x-35=-63
9x=-63+35
9x=-28
x=-28:9
x=-28/9
b)
5(x+3)=3(x-5)
5x+15=3x-15
5x-3x=-15+15
2x=0
x=0:2=0
c)
2(-x+4)=-3(x+1)+23
-2x+8=-3x-3+23
-2x+3x=-3+23-8
x=12
d)
1-2[3-(4-x)]=-7
1-2(3-4+x)=-7
1-2(-1+x)-7
1+2-2x=-7
3-2x=-7
-2x=-7-3
-2x=-10
x=-10:(-2)
x=5
e)
2(x+6)-(5-3x)=2(-x+9)+3
2x+12-5+3x=-2x+18+3
5x+7=-2x+21
5x+2x=21-7
7x=14
x=14:7
x=2
f)
225:(x-3)=-15
225/(x-3)=-15
225=-15(x-3) | : 15
15=-(x-3)
15=-x-3
x=-15-3
x=-12
