I don’t know how to do it..

Step-by-step explanation:

Hello,

let's note e the angle that we are looking for

We know that in a triangle the sum of angles is 180 so we can write

For the BDE triangle

    (1) 4x + 5x -1 + e = 180 <=> 9x + e - 1 =180

for the ACE triangle

   (2) 4x + 6x-15 + e = 180 <=> 10x + e -15 = 180

So (2)-(1) gives

   10x + e -15 - (9x + e - 1 ) = 180 - 180 = 0

   <=> 10x + e -15 -9x -e +1 = 0

   <=> x -14 = 0

   <=> x = 14

and then we replace in (2) it comes

10*14 + e  - 15 = 180

<=> 140 + e - 15 = 180

<=> e = 180 + 15 - 140 = 40 + 15 = 55

so m<E =

Hope this helps

2 x t divided by n

step-by-step explanation: