Hello, Final question for today (Been doing a few questions today, got around 30 done but this one has stumped me now!)
Question 11. Using the substitution method, determine exactly the coordinates of the intersection of the two straight lines 2x-y = 2 and 3x-2y = 1.
The substitution method for me generally meant that you'd plug one of the formulas into the other formula and calculate. Normally I understand it because it has only one x or y to resolve, but I'm not sure how to substitute in this case when both formulas have answers to them already.
If it was something like
2x – 3y = –2
4x + y = 24
I get you do something like 2x-3(–4x + 24)=-2 and go from there because 4x+y=24 is easy to convert but This above one has me stumped. Any advice?
use 2x-y = 2 and arrange it to
-y = -2x + 2
y = 2x - 2
now sub that into the other equation:
3x-2y = 1
3x - 2(2x - 2) = 1
3x - 4x + 4 = 1
-x = -3
x = 3
put this back into y = 2x - 2
and solve for y = 4
so the point is (3,4)
always check to see if your answer satisfies both equations , it does.