Answer: Hello there!
here we have two equations:
1) x + 3y = 7
2) 2x + 4y = 8
a) first we want to isolate x in the first equation:
x + 3y = 7
x = 7 -3y
done!
b) now we want to replace it in the second equation, and in this way get a equation that depends only on the variable y.
2x + 4y = 8
2(7 - 3y) + 4y = 8
c) now we sole this equation and obtain the value of y.
14 - 6y + 4y = 8
14 - 2y = 8
-2y = 8 - 14 = -6
y = 6/2 = 3
d) now we have the value of y, and we can substitute it on the equation that we got in the part a)
x = 7 - 3y
x = 7 - 3*3 = 7 - 9 = -2
e) now we knowt that x = -2 and y = 3, then the pair (x,y) can be written as:
(-2,3).
