# maths

simultaneous equations

x + 2y = 4
3x - 4y = 7

x=3 and y = 1/2

i need to explain how i got this answer and do not know how to do that?

i am confused about how you got this answer what working out is it

the object in "elimination" is to get the coefficients of either the x or the y to be opposites, so that when you add the equations, they will cancel

so look at the first equation, if we multiply it by 2 we could have a 4y which is the opposite of -4y from the second equation.
let's do that

2x + 4y = 8 ....... the first times 2
3x - 4y = 7 ........ no change
------------
5x + 0 = 15 .........I added them
x=3 ..................I divided both sides by 5

now take that x value and substitute it back into the easier of the two original equation to get y = 1/2

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