Solve the simultaneous equations: 2x+2y = 10 and 7x + 4y = 26

The first step with any simultaneous equation is to cancel out one of the variables. Here, 2y is a factor of 4y (it fits into 4y twice) so we can multiply the 1st equation by 2 to give us 4x+4y = 20.This gives us 4x + 4y = 20 and 7x + 4y = 26. We can now subtract the 1st equation from the second ( do it this way round to avoid negative numbers). This gives us 3x= 6. now we can find x. divide both sides by 3 to give x=2. now, we can substitute x=2 into an equation to find y. choose the first one as it is easier. 2(2) +2y = 10 gives us 4 +2y=10. rearrange this to give 2y=6 and ultimately y=3. now we need to double check this works. choose either equation but preferably use the one you didn't use earlier, so the second in this case and substitute x=2 and y=3. 7(2) + 4(3) = 14 + 12 = 26

Answered by Sylvia M. Maths tutor

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