13
6 + 12 - 5 = 13
the answer is a
4c+2 = 3c+9 4c-3c = 9-2 c = 7
A.
If 9 - 2c + 3 = -13, then c would be 12.5
13+c = -39 c = -39-13 c = -52
13
6 + 12 - 5 = 13
-4 + c = -9 -4 + 4 + c = -9 +4 c = -9 + 4 c = -5
a=5: c=4
2c + 4 - 3c = -9 + c + 5 -c + 4 = c - 4 -2c = -8 2c = 8 c = 4
the answer is a
This is the associative law for addition: If a, b, c are any numbers then: a + (b + c) = (a + b) + c
144 Formula: c= (a2)+(ab)
4c+2 = 3c+9 4c-3c = 9-2 c = 7
Use the quadratic formula, with a = 1, b = 7, c = 9.