Answer:
5. y = 9
6. x = -6
Explanation:
You want the y-value of the solution to one set of equations, and the x-value of the solution for another set.
5. y-value
It is convenient to eliminate x from the equations by subtracting the second equation from twice the first:
2(y) -(y) = 2(x +4) -(2x -1)
y = 9 . . . . . . . simplify
6. x-value
It is convenient to eliminate y from the equations by adding twice the first equation to the second:
2(y) +(-6x -2y) = 2(-2x +1) +(10)
-6x = -4x +12 . . . simplify
0 = 2x +12 . . . . add 6x (to make the x-coefficient positive)
0 = x +6 . . . . . divide by 2
-6 = x . . . . . . . subtract 6
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Additional comment
We used elimination to get an equation in the variable of interest. There is no reason why you have to do it this way. The equations in 5 are easily solved by equating the y-expressions: x +4 = 2x -1 ⇒ x = 5 ⇒ y = 5+4 = 9.
You can always solve the equations using your favorite method, unless the solution method is specified for you. A graphical solution is often quick and easy.