Explicação passo a passo:
a)12x-10=5x+11
12x-5x = 11+10
7x = 21
[tex]x=\frac{21}{7}[/tex]
x=3
b)7x+5=68-2x
7x+2x = 68-5
9x = 63
[tex]x=\frac{63}{9}[/tex]
x = 7
c)2(7x+2)+12(x+1)=2
14x+4+12x+12 = 2
14x+12x = 2-4-12
26x = -14
[tex]x=-\frac{14}{26}[/tex]
d)-2(y-3)=18
-2y+6 = 18
-2y = 18-6
-2y = 12 .(-1)
2y = -12
[tex]y=-\frac{12}{2\\}[/tex]
y = -6
e)4(y-1)-2(3y+4)=6
4y-4-6y-8 = 6
4y-6y = 6+4+8
-2y = 18 .(-1)
2y = -18
[tex]y=-\frac{18}{2}[/tex]
y = -9
f)3(2x-5)=9-2x
6x-15 = 9-2x
6x+2x = 9+15
8x = 24
[tex]x=\frac{24}{8}[/tex]
x = 3
g)10-4x=9+2x
-4x-2x = 9-10
-6x = -1 .(-1)
6x = 1
[tex]x=\frac{1}{6}[/tex]
h)2(7x+2)+12(x+1)=1
14x+4+12x+12 = 1
14x+12x = 1-4-12
26x = -15
[tex]x=-\frac{15}{26}[/tex]
i)-2(x-3)=18
-2x+6 = 18
-2x = 18-6
-2x = 12 .(-1)
2x = -12
[tex]x=-\frac{12}{2\\}[/tex]
x = -6
j)4(a-1)-2(3a+4)=6
4a-4-6a-8 = 6
4a-6a = 6+4+8
-2a = 18 .(-1)
2a = -18
[tex]a=-\frac{18}{2}[/tex]
a = -9
