Question

AB congruent CD. Find the length of BD.

Answer 1

BD=4

Explanation:

Since AB and CD are congruent (or the same length) we can equal the corresponding equations for the two:

2x+5x+7=5x+7+3x-4

(simplify)

7x+7=8x+3

(get variables to one side)

7x+7-8x=3

7x-8x=3-7

(simplify)

-x=-4

(multiply by -1 to get x by itself)

x=4

Now, plug x=4 into the BD equation (3x-4)...

3(4)-4=BD

12-4=BD

8=BD

Answer 2

8

Explanation:

2x+5x+7=3x-4+5x+7

7x+7=8x+3

x=4

BD=3(4)-4=12-4=8

Hope this helps!