Equation given:
4 -(2a + 7) = 9
When there is a minus (-) next to the parenthesis, there is an invisible negative one (-1).
4 -1(2a + 7) = 9
Distribute:
4 -2a -7 = 9
There is a like-term which is 4 and -7. 4 -7 = -3
Combine like-terms:
-3 -2a = 9
Solve the two-step equation:
-3 -2a = 9
Turn -3 to +3 and add 3 to 9
-3 -2a = 9
+3 +3
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-2a = 12
Divide -2a to 12
12/-2 = -6
a = -6
