System of equations with substitution (algebraic) I need a lot of help with
Solve the system of equations using subtractions. Show all work!
#1 y=x+3 3y+x=5
#2 x=-2y+9 -2x+3y=10
and using desmos graphing calc. I already figured out that for #1 X=-1 and Y=2 and so the solution is (-1,2) for and for #2 X=1 and Y=4 and the solution = (1,4)
but I need to know how to do it without using desmos, can you show me it step by step please, like the formula and stuff because I don't understand how to do it