Answer:
D). 
Step-by-step explanation:
<u>STEP 1a:</u> Find the last angle of the triangle. ( which is angle A)

<u>STEP 1b:</u> Solve the equation for A by adding 90 and 45.

<u>STEP 1c:</u> Then Move all terms not containing A to the right side of the equation by subtracting 135 from both sides of the equation

<u>STEP 1d:</u> Subtract 135 from 180.

STEP 2a: Find side b next.
STEP 2b: The cosine of an angle is equal to the ratio of the adjacent side to the hypotenuse.

STEP 2c: Substitute the name of each side into the definition of the cosine function.

STEP 2d: Set up the equation to solve for the adjacent side, in this case b.

STEP 2e: Substitute the values of each variable into the formula for cosine.

STEP 2f: Cancel the common factor of 2.

HOPE THIS HELPS!
Answer:
Step-by-step explanation:
since AD is a median it implies that triangle ABC is bisected to two equal right angled triangle which are ADB and ADC.
FE is parrallel to BC and cuts AB at F and AC at E shows that there are two similar triangles formed which are AFE and ABC.
Recall that ADC is a right angled triangle, ED bisects a right angled triangle the the ADE =
.
Now, Let FD bisect angle ADB,
then ADF =
too.
Since AFX is similar to Triangle ABD and that Triangle AEX is similar to Triangle ACD, then EDX is similar to FDX
FDE = ADF + ADE = 
Algebraic expression: 100 = 25 + n
Answer: n = 75
m = 4b+3 mikes age
m +b <138 mike +brother less than 138
4b+3+b<138
5b +3< 138
b< 135
b <27
The oldest the brother can be is 26