The answer is 2.5, but if you say it isn't then maybe it can be as a fraction
or
.
All I can say is that your equation is wrong
The answer is D. M=7
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explanation
7+3(7)=28
7+21=28
28=28
making the D.M=7 as true.
You can write a proportion because the two triangles are similar
=
(the second fraction is longer because I added the full lengths of the larger triangle) cross multiply to get (x)(x + 1 + x - 2) = (x - 2)(x + x + 5)
which simplifies to (x)(2x - 1) = (x - 2)(2x + 5)
then 2x² - x = 2x² + 5x -4x - 10
then 2x² - x = 2x² + x - 10
then 2x² = 2x² + 2x - 10
subtract 2x² from both sides to get 0 = 2x - 10
add 10 to both sides to get 10 = 2x
divide both sides by 2 to get 5 = x