Question 183802
1) 4(a-3)=3-(a+5) 
4a - 12  = 3 - a - 5

5a -12 = -2

5a = 10

a = 2
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2) 3z=2(z-3)+9 

3z = 2z - 6 + 9

z = 3
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3) 8a-(a-7)=21 

8a - a + 7 = 21

7a = 14

a = 2
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Cheers,
Stan H.