Answer:
1) x=5
2) x=7
3) x=8
4) x=4
5) x=7
6) x=8
Explanation:
Since each pair is similar, their sides are in ratio:
1)
(2x+2)/6=18/9
2x+2=2*6
2x=12-2
x=10/2
x=5
2)
(x-2)/4=10/8
x-2=1.25*4
x=5+2
x=7
3)
(3x-6)/12=24/16
3x-6=1.5*12
3x=18+6
x=24/3
x=8
4)
(2x+4)/15=16/20
2x+4=0.8*15
2x=12-4
x=8/2
x=4
5)
(x+2)/15=6/10
x+2=0.6*15
x=9-2
x=7
6)
(-3+x)/6=10/12
-3+x=6*(10/12)
x=5+3
x=8