a+bx5-c+2-ax9=b+ax(-c+5)+2a+8x9 nilai a adalah....

a+bx5-c+2-ax9 = b+ax(-c+5)+2a+8x9
a-9a+5b-c+2 = b-ac+5a+2a+72
-8a+5b-c+2 = 7a+b-ac+72
-8a-7a+5b-b-c = 72-2-ac
-15a+4b-c = 70-ac
-15a+ac = -4b+c+70
15a-ac = 4b-c-70
a(15-c) = 4b-c-70
a = 4b-c-70
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15+c

jadi a = 4b-c-70
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15+c