Question

4x + 9y = 29
x = 5y - 87

Answer 1

what I would do here is substitute "5y -87" for x in the first ecquation, since the second equation is already in the form "x=..." so:


4*(5y-87)+9y=29


getting rid of the bracket:

20y-348+9y=29


adding up:

29y=29+348

29y= 377

dividing by 29:

y=13


and now we can calculate x, which is 5*13-87=65-87=-22

so x=-22