12. If ABCD is a parallelogram, find mzC.
A
B
(5x + 38)
(8x - 19°
С
D

85°

Step-by-step explanation:

m<B = m<D (opposite angles of a parallelogram)

Therefore:

5x + 38 = 8x - 19

Collect like terms.

5x - 8x = -38 - 19

-3x = -57

Divide both sides by -3

x = 19

m<C + m<B = 180° (consecutive angles of a parallelogram are supplementary)

(5x + 38) + m<C = 180°

Plug in the value of x

5(19) + m<C = 180°

m<C = 180 - 95

m<C = 85°

y = - 6

step-by-step explanation:

given the point (- 2, y) lies on the graph then it is a solution of it's equation.

substitute x = - 2 into the equation for value of y

y = 3(- 2) = 3 × - 2 = - 6

the point on the graph is (- 2, 6)

38.5

step-by-step explanation:

lets say, first number = r

second number = 3r+7

total = 49

(r)+(3r+7)= 49

4r+7 = 49

4r = 42

r = 42/4

r= 10.5

3r+7 = 3(10.5)+7 = 38.5

hope this