Question

Find angle abc (2x+14) (x+7)

Answer 1

It's a complementary angle, so just solve for x and subtract the CBD from 90, 
First, we have to solve for x.
2x + 14 + x + 7 = 90
Combine like terms
3x + 21 = 90
Balance, subtract 21 from each side.
3x = 69
Divide 3 from each side
x = 23.
So know that we know x is 23, we can go about it 2 ways, subtracting the other angle with 90 or just substituting the variable, I'd just substitute the variable for it so just do 23 + 7. That equals 30, angle ABC = 30.

Answer 2

Angles represented by 2x+14 and x+7 must add up to 90 degrees.  Thus,

2x+14 + x+7 = 90, so that

3x + 21 = 90, or 3x = 69, or x = 23.

Then angle ABC is x+7, or 23+7, or 30 degrees.

If that's the case, then angle CBD must be 60 degrees.  Is it?
Subst. 23 for x in 2x+14:  2(23)+14 =46+14 = 60 (degrees).  YES.