Question

solve by the linear combination method
5u + 4v = -18
0.04u - 0.12v = 0.16
Please help, I don't understand how to solve this...

Answer 1

so what u do in combination method is that u add the two equations together
but before u add them u have to make sure that one variable cancels out after u add them and to do that u multiply or divide all the parts one or both equations.
so, i am going to cancel the variable u
multiply all parts of second equation by -125 to get -5u at the bottom which could be cancelled out
so -125(0.04u - 0.12v = 0.16)
-5u+15v=-20

v=-2
then substitute the value of v into any of the equations and solve for u
u can do that yourself