# Substitution method

I need to solve for x and why

x+y=4 y+-x=3

 Ionse Posts: 7, Reputation: 1 New Member #2 Apr 3, 2007, 08:57 PM
You have to determine in one equation what x ( or why ) and then sub it into the other equation.

X + why = 4 turns into x = 4 - why , then you sub that value in for x in the other equation.

Y + -(4-y) = 3 which is simplified into why -4 + why = 3 and then simplified more yet again into
2y = 7 or why = 3 1/2

Using the value of why = 3 1/2 you can find out that x = 1/2

Very exciting imo
 cool_dude Posts: 125, Reputation: 48 Junior Member #3 Apr 4, 2007, 08:05 AM
Personally I think its faster to use elimination method in this question. Although it depends on preference. You can just add the two equations together.

Ex.
x+y=4
+ y+-x=3
=
2y = 7
why = 7/2

## Check out some similar questions!

Substitution method problem [ 5 Answers ]

2a - 3b = -13 -b = -2a - 7 Help?

Algebra substitution [ 1 Answers ]

Substitution 9x-2y=3 3x-6=y

Substitution with a fraction [ 3 Answers ]

Why = -x/2 2x - 3y = -7 I have reached this point: 2x - 3(-x/2) = -7 Can someone help me? Thanks!

Substitution problem that has me confused! [ 9 Answers ]

5s + 10t = 3 2s + 1t = 0 Any help is appreciated!:confused: