Answer:
is there more to the question?
Answer:
Yes
Step-by-step explanation:
If they're perpendicular, that means that angle ECM = 90 degrees and angle ACE = 90 degrees. To figure out if this works, plug that into the two equations they give:
ECM = 3x + 15
becomes
90 = 3x + 15
75 = 3x
25 = x
ACE = 4x - 10
becomes
90 = 4x - 10
100 = 4x
25 = x
Since you get x = 25 for both, you know that they are perpendicular because they both measure 90 degrees
Answer:
x = 10
Step-by-step explanation:
Use Pythagorean theorem to find the value of x
Focus only on one half of the triangle
if we slice the triangle in half, we get a right angle triangle
the base will now be 12/2 = 6
Pythagorean theorem says that 
plug 6 as a and 8 as b.
this should give you 100
now take the square root to find c (which equals x)
Ta-da!
If the fraction cannot be simplified any more, you can multiply both the numerator and denominator by an number.
5/6 (multiply the top and bottom by 2) is the same as 10/12
8/22 (can be simplified by dividing top and bottom by 2) is 4/11
25/30 (simplified by dividing by 5) is 5/6
5/15 (simplified by dividing by 5) is 1/3
Hope this helps!