Question

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Answer 1

1) 3/5=9/x (cross multiply)
3x=5(9)
3x=45
x=15

2) 2/4=x/12 (cross multiply)
2(12)=4x
24=4x
6=x

3) 10/x=5/9 (cross multiply)
10(9)=5x
90=5x
18=x

4) 5/6=x/18
5(18)=6x
90=6x
x=15