Look at the figure. How can you prove the triangles are congruent? A. ∆ABD ≅ ∆CDB by the SAS Postulate.

B, It is not possible to determine if the triangles are congruent.

C. ∆ABD ≅ ∆CDB by the SSS Postulate.

A. ∆ABD ≅ ∆CDB by the SAS Postulate.

Step-by-step explanation:

You know lines AB and DC are congruent because of the lines on each. Additionally, angles B and D are congruent for the alternative interior angles rule and they also are marked as congruent in the image. Finally, DB is congruent to DB because of the reflexive property. So you have two sides and the included angle, this makes the SAS postulate true.

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