Solve the simultaneous equations
2x + 4y =1
3x– 5y =7
the first thing you want to do is make both of the equations the same. the way you would do this is:
2x + 4y =1 ×5
3x– 5y =7 ×4
10x + 20y =5
12x - 20y =28
the reason for doing this is to find what one of th3 equations equal to. meaning that by making one of the sets of letters+numbers the same, we can find out what the other set of letters+numbers to find what x and y equal to.
so we have to:
10x + 20y =5 -20y
12x - 20y =28 +20y
22x =33
the season for adding the 10x and 12x is because when adding a minus and an addition number we add. you would only need to subtract if it's sss (same sign subtract) which isn't in this case.
with 22x =33, we divide both sides by 22 to get x on its own.
making x to equal 1.5
to find y, we have to sub in x with 1.5
so, you would do:
2 × 1.5 +4y =1
2 × 1.5 = 3
3 + 4y =1
-3 -3
4y = -2
y = -1/2
x = 1.5
y = -1/2