How do you solve #x=y+4# and #5x+3y=-20# using substitution?
First we substitute in our value for
Then you expand the bracket and simplify it to find
Now we use our value for
We can then check our answer by substituting both values into the other equation:
So we know it's right!
It's really important to check your answers, as in a test, it could save you a whole load of marks despite only taking a few seconds:)
Hope this helps; let me know if I can do anything else:)