substitution method what is the cordinate for x+y=5 3x-2y=10

Question

i need to now the both the numbers for x and y. x=? y=?

Answer 1

substitution method what is the cordinate for x+y=5 3x-2y=10
i need to now the both the numbers for x and y. x=? y=?

x + y = 5      3x - 2y = 10

We want either the x or the y to have the same
coefficient in both equations. Let's make it the y
by multiplying the first equation by 2. Actually,
we will have a +2 and a -2, but that makes it easier.
We can add the equations instead of subtracting.

2(x + y) = 2 * 10
2x + 2y = 20

Now add the two equations.

    2x + 2y = 20
+ (3x - 2y = 10)
-----------------------
    5x        = 30
5x = 30
x = 6

Substitute that into one of the equations to
solve for y.

x + y = 5
6 + y = 5
y = 5 - 6
y = -1

You have x = 6 and y = -1.

Comments

Slight slip: 2(x+y)=2*5=10 (not 2*10=20), so x=4 and y=1. Easily done. Otherwise good, clear answer, although you used elimination rather than substitution initially. So who cares?!

Answer 2

Given x+y=5....(1)
3x-2y=10....(2)

From equation (1)
y=5-x

Substitute in equation (2)
3x-2(5-x)=10
3x-10-2x=10
x= 20

y= 5-20=15

Know more about Substitution Method

Comments

3x-2(5-x) is 3x-10+2x. So x=4 and y=1. Bad luck! Good idea to check answers in original equations. That's how I find out when I've made a similar error.