1. a)5x+45=135=>5x=90=>x=18
b)12x-60=144=>12x=204=>x=17
c)270-15x=180=>-15x=-90=>x=6
d)(x-2)=441=>x=443
e)18x-9=153=>18x=162=>x=9
f)14x+28x=588=>42x=588=>x=14
2. a+b=163
a+13=b
a+a+13=163=>2a=150=>a=75
75+b=163=>b=163-75=>b=88
3. c+d=348
c=d+42
d+42+d=348=>2d=306=>d=153
c+153=348=>c=195
4. x+y=232
y=3x
x+3x=232=>4x=232=>x=58
58+y=232=>y=174