I need to solve this by using the substitution method. Then graph.......please help.

y=-x+1
2x-y=5

Question

I need to solve this by using the substitution method.  Then graph.......please help.

y=-x+1
2x-y=5

katrinakaif · Answer

Subsititute in for 'y' in the second equation using the first:
2x - (-x + 1) = 5 
2x + x + 1 = 5 
3x + 1 = 5 
3x = 5 - 1 
3x = 4
 x = 4/3

karatechopper · Answer

ok well u know what y equals..so plug in the answer for y! meaning u would plug this in..
2x-(-x+1)=5

karatechopper · Answer

then you would solve from there!

anonymous · Answer

ok thats what I got was x=4/3 but the book says (2,-1)

katrinakaif · Answer

Did you try graphing the expressions?

anonymous · Answer

no I don't know how

katrinakaif · Answer

Your first equation is in y=mx + b format

anonymous · Answer

oh ok I remember kinda how to do that......I will just have to look back in the book

katrinakaif · Answer

Then turn your second equation to y= mx +b format too: 
2x-y=5
-y = -2x + 5 
y = 2x - 5

anonymous · Answer

ok thanks

katrinakaif · Answer

If you need help finding it, post once again and we can help you complete it

anonymous · Answer

will do