What would be the value of m?

126°

Step-by-step explanation:

First you need to find the 3rd inside angle.

72+54+x=180

126+x=180

x=54

Once you have the 3rd inner angle, you can take 180 and subtract it from it so you would have 180-54 which is 126

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -