Solve for both systems: 7x+7z=70 and 2x + 13z = 97

7x+7z=70

7x-7x+7z=70-7x

7z=70-7x

7z/7=70-7x/7

z=10-x

2x + 13z = 97

2x + 13(10-x) = 97

2x + 13(10) (13)(-x) = 97

2x+130-13x=97

130-11x=97

130-130-11x=97-130

-11x=-33

-11x/-11=-33/-11

x=3

z=10-x

z=10-3=7