a) Find the values of k and c in the equation y=c+kx-x^2
b) Find the co-ordinates of the highest point of the graph.

Please help, thank you!

Would be glad to help and if you tell us where you are stuck, we're more than happy to help.

Basically, you have to use your standard quadratic formula

x{\small_1}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

In your case, k is the same as b and a is -1

Good luck.

Thank you for your help, I don't know how to use the quadratic formula to solve this. Will the answer be numbers or an expression?

It will be an expression as you do not have any number for c, k and b .