If A=5x-2y+4, B=-4x+6y-1 and C=11y-10, find A+B-C.
Step 1: Find the value of A+B
Given A=5x-2y+4, B=-4x+6y-1, C=11y-10
A+B=5x-2y+4+-4x+6y-1
A+B=5x-4x+-2y+6y+4-1
∴A+B=x+4y+3
Step 2: Find the value of A+B-C
A+B-C=A+B-C
A+B-C=x+4y+3-11y-10
A+B-C=x+4y-11y+3+10
∴A+B-C=x-7y+13
Hence the value of A+B-C is x-7y+13
In a cyclic quadrilateral ABCD, ∠A=(2x+4)∘,∠B=(y+3)∘,∠C=(2y+10)∘,∠D=(4x−5)∘. Find the four angles.