Question 427937
Substitute 3, in for x, and solve for a:


x + 3 = ax + 9 when x = 3
3 + 3 = a(3) + 9 {substituted 3 in for x}
6 = 3a + 9 {combined like terms on left side}
3a = -3 {subtracted 9 from both sides}
a = -1 {divided both sides by 3}


C. -1
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