Combining like terms simplify each expression n - 4 - 9

N - 13, because -4 and -9 are like terms

N-4-9
like terms- -4, -9
-4+-9=-13
so its n-13

In the first triangle 80+20+p=180 (since sum of all angles of a triangle is 180)so p= 80also in second triangle 55+45+q=180 (since sum of all angles of a triangle is 180)so q=80so we can conclude that p=80 degrees q=80 degrees so p=q=80 degreeshence option b is correct