Question

find the value of y

Answer 1

those are length measurements right?

Answer 2

if so you might want to solve for x first
then use similar triangles to find y

Answer 3

Okay, but i dont know how to

Answer 4

we are given that 5x+8 is equal to 21x

Answer 5

can you solve for x now?

Answer 6

I'm asking if you know how to solve 5x+8=21x for x?

Answer 7

Subtract 8 from both sides?

Answer 8

8 has no friends on the other side
why not trying to subtract 5x on both sides

Answer 9

i got you,okay so x=8

Answer 10

wait did you subtract 5x on both sides?
8=21x-5x
8=16x
now divide both sides by 16

Answer 11

2?

Answer 12

8/16 shouldn't be 2 but 1/2

Answer 13

these are two difference numbers

Answer 14

okay so i got 0.5

Answer 15

anyways x=1/2
which means if x=1/2 then 21x is 21/2
or if you plugged x into the other expression 5x+8 you should still get 21/2

moving the bar up to show the similar triangles in a more obvious way: