Help me!!!!! No 4 dan 5

4. 9/9+3= 12/(12+p)
9/12 = 12 /(12+p)
3/4= 12 / (12+p)
Dikali silang
36+3p = 48
3p= 48-36
P = 12:3
P = 4
5. 6/10 = 3/x
Dikali silang
6x = 30
X = 30 : 6
X = 5
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