Four triangles are shown. One side of each triangle lies on a ray, and the triangles are not drawn to scale. Based on these triangles, which statement about x is true?

Choice a :  x= 102 degrees because 180°- (63°+39° ) = 78° and 180° - 78° = 102°

Step-by-step explanation:

Two angles are given as  63° and 39°

To find the third angle we subtract the other two angles from 180°

180°- 63°-39° gives 78°as the third inner angle .

The third angle and the outer angle x lie on the straight line making a total of 180°.

To find x we again subtract the inner angle 78° from 180°.

This gives the value of x to be 102°

180°- 78°=102°

Choice a is the best option.

Step-by-step explanation:

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18