how to do this? 3x-4y=-1 and x+y=5 in substitution

Question

anonymous · Answer

haha. okay, so apparently the first answer wasn't good. you need to solve one of your equations for one of the variables. for example, solving the second equation for "y" gives
y = 5 - x

anonymous · Answer

this can be substituted. to make this easier, put the right hand side of your solved equation directly into the left, using parentheses, like this:
3x - 4(5-x)=-1

anonymous · Answer

okey.okey okey yes i forgot .tnx

anonymous · Answer

y = 5 -x

3x - 4y = -1
3x - 4(5-x) = -1 (see azeotrope's explanation)
3x -20 + 4x = -1 distribute -4 to the terms inside the parenthesis
7x -20 = -1 combine similar terms
7x = -1 + 20 transpose -20 to the other side
7x = 19 do the operation
x = 19/7 divide both sides by 7