Y=1
To get it, you use the method of substitution. So you swtich the top y by the equation of the bottom=-3x+6=-7x+10. You first add 7x to each side=4x+6=10 then you minus 6 from each side=4x=4 which is 1
15=3b
15/3 = 3b/b
5= b
Isolate the variable by diving 3 on both sides