I don’t understand, explain also

32

63

Step-by-step explanation:

m<BCA=180-148-32 Subtract 180-148 b/c x<BCA is along the straight line ACD. A straight line will have an angle of 180 degrees.

m<CAB=180-32-85=63 All triangles have angles which add up to 180 degrees. Subtract 32 and 85 from 180 to get 63.

Step-by-step explanation:

148 + x = 180

x = 180 - 148

x = 32

Find m<CAB basically means find the measure of the angle of A ( m<A )

m<B + m<A + x = 180

85 + m<A + 32 = 180

117 + m<A = 180

m<A = 180 - 117

m< A = 63, so m<CAB = 63

And m<BCA means find the measure of angle C(m<C) or as we did it earlier as x, which is the same thing.

So m<BCA = 32

2,160 π

step-by-step explanation:

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 -