4a-5b=7; 4a+5b=17
Solve for a and then solve for b or either or of the variable
4a-5b=7
4a=7+5b
A=(7+5b)/4 then plug into a for 4a+5b=17
4((7+5b)/4)+5b=17
7+5b+5b=17
7+10b=17
10b=17-7
10b=10
B=1 then plug into solved a=(7+5b)/4
A=(7+5(1))/4
A=(7+5)/4
A=12/4
A=3
A=3;b=1
