Solve using substitution method. 4x-y=5 4x+4y=-4solve the linear system from the problem using elimination.

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lemjay eNotes educator| Certified Educator


EQ1: `4x-y=5 `                         EQ2: `4x+4y=-4`

Note that we may re-write EQ2 as:


Then, substitute this to EQ1.




Isolate -5y.



Then, isolate y.


Substitute the value of y to  4x=-4-4y and solve for x.

`y=-9/5` ,   `4x=-4 -4(-9/5) = -4+36/5= 16/5`

                   `x=(16/5)/4 = 4/5`

Hence, the solution to the given system of equations is `x=4/5` and `y=-9/5` .