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difficult 9-1 gcse maths questions

Hello

i think this is the write place to ask questions?

I am stuck on q16 and q18 of this paper: https://crashmaths.com/wp-content/uploads/2017/04/GCSESETCP1QP.pdf

i have tried to do q16 by finding the minimum point by finding the intersection points and there midpoint, but i get 5 + (square root) 2 and 5 - (square root) 2 and that has a midpoint of 10 + 2 (square root) 2 divide 2, which doesn't make sense??

for q18 i have no idea :frown:

Reply 1

boriapple

For q16 try completing the square and remember what the numbers you get mean. Also, the midpoint between the roots

x=5\pm 5\sqrt{2}

is:

\frac{5+5+5\sqrt{2}-5\sqrt{2}}{2}=\frac{10}{2}=5

which you could also put into your equation for y.

EDIT:
It seems you made a mistake in finding your midpoint, even though you got the roots wrong you would have gotten the correct answer if you checked your negatives and positives.