exam Maths Puzzle Numerical Ability

Can someone please show me how this is done. The way I am doing it the teacher says is incorrect.

x^2 - 4x - 60 = 0

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exam Other Question

Y=A/X
2< or = X < or = 6
4/3 < or = Y < = B

A=?
B=?
I have that x=4
Same thing with this one can someone find the exact value of tan 15 degree without using tables or a calculator. please show work.