Question

Solve each simultaneous equation
X-Y=73
X-2Y=4

Answer 1

subtract the two

Answer 2

Can you show me?

Answer 3

i X-Y = 73
ii X-2Y = 4

i-ii (X-Y)-(X-2Y) = (73)-(4)
Y =

Answer 4

okay ummm this format you put it in is really confusing... but i understand what you did. Sooo whats next?

Answer 5

did you find Y ?

Answer 6

no

Answer 7

If you use substitution, you can solve the first equation in terms of one variable and solve for the other. So:
x - y = 73
(+y) (+y)
x = 73 + y

Then you have
x - 2y = 4

Since you have a value for x in terms of y, you can also write the equation as

(73 + y) - 2y = 4

If you solve for y, you will get a number you can substitute for y in one of the other equations.