Question

Find the solution to the system of equations: x + 3y = 7

and 2x + 4y = 8
1. Isolate x in the first equation:
2. Substitute the value for x into the second equation:
3. Solve for y
x = 7 - 3y
2(7 – 3y) + 4y = 8
14 - 6y + 4y = 8
14 - 2y = 8
-2y = -6
y = 3
x + 3(3) = 7
4. Substitute y into either original equation:
5. Write the solution as an ordered pair:

Answer 1

( -2 , 3 )

...................................................................................

Answer 2

(-2,3)

Explanation:

Doing it the way you did and working out the problem you substituted 3 into, x+3(3)=7, 3(3) is 9 and then you subtract 9 from both sides.

7-9=-2

x=-2

Then all you have to do is put it into ordered pairs.

(x,y)

(-2,3)