Question

Find the value of x.

Answer 1

x=3

Explanation:

I guessed and checked which x value would make ABC proportional to DBE. If x=3, than DB=8 which is double BE. If x=3, than AB=14 which is double BC. Since it is proportional, It should be correct. I don't remember the actual way you solve this with a formula but this makes sense to me.

Answer 2

x=3

Explanation:

We can use ratios to solve since the triangles are similar

x+5 4

------------ = ---------------

x+5 +2x 4+3

Simplifying

x+5 4

------------ = ---------------

3x+5 7

Using cross products

7(x+5) = 4(3x+5)

Distribute

7x+35 = 12x+20

Subtract 7x from each side

35 = 5x+20

Subtract 20 from each side

15 = 5x

Divide by 5

3 =x