l
Solve for u
15u + 640 = 55u
Group our variables 15u and 55u
subtract 55u from both sides
15u + 640 - 55u = 55u - 55u
-40u + 640 = 0
15u | |
15 |
= |
640 |
15 |
Group our constants 640 and 0.
subtract 640 from both sides
-40u + 640 - 640 = 0 - 640
-40u = -640
-40u | |
-40 |
= |
-640 |
-40 |
u = 16