x = 3 4 x + 9 = 4 ⋅ 3 + 9 = 12 + 9 = 21
Just insert the number. (3) 4(3)+9 12+9=21
When substituting x = 3 into the expression 4 x + 9 , we find that the value is 21 . This is calculated by multiplying 4 by 3 to get 12 , then adding 9 to that result.
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