## Welcome to H3 Maths

Blog Support for Growing Mathematicians

## Posts tagged with maths error

### Less than excellent use of Excel…

July27

Yes, it happened to me – I was using Excel to finish my tax claim and then sent it off to my accountant. He remarked to me, over lunch, that I had made a mistake in my Excel calculations. Yes, I had made the kind of error that is just so easy to do – […]

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NCEA Level 2 Algebra Problem. Using the information given, the shaded area = 9, that is:
y(y-8) = 9 –> y.y – 8y – 9 =0
–> (y-9)(y+1) = 0, therefore y = 9 (can’t have a distance of – 1 for the other solution for y)
Using the top and bottom of the rectangle,
x = (y-8)(y+2) = (9-8)(9+2) = 11
but, the left side = (x-4) = 11-4 = 7, but rhs = y+? = 9+?, which is greater than the value of the opp. side??
[I think that the left had side was a mistake and should have read (x+4)?]