Find the value of y and the measures of angles ABD, DBC, and ABC. Show your work for credit.

Find the value of y and the measures of angles ABD, DBC, and ABC. Show your work for credit.
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ABD + DBC = ABC
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(4y+7) + (3y+12) = (10y-5)

4y + 7 + 3y + 12 = 10y - 5
7y + 19 = 10y - 5
19 + 5 = 10y - 7y
24 = 3y
8 = y
Angle ABD = 4*8 + 7 = 39
Angle DBC = 3*8 + 12 = 36
Angle ABC = 39 + 36 = 75

(4y+7) + (3y+12) = (10y-5)

first add whats addabl

4y+7 + 3y+12 = 10y-5 --------> 7y + 21 = 10y - 5

then substract 10y on both side

7y - 10y + 19 = 10y - 10y - 5 -- -- ---> -3y + 19 = -5

substract -19 on both side

-3y + 19 - 19 = -5 -19 --------> -3y= -24

finally divide both side by -3

(-3y)/-3 = (-24)/-3 ---------> y = 8



ABD = 4*8 + 7= 32 + 7 = 39 degrees
DBC = 3*8 + 12 = 24 + 12 = 36 degrees
ABC = 10*8 - 5 = 80 - 5 = 75 degrees

I think this is simple algebra
so bring all the y's to one side.
4y+3y-10y= -5-12-7
-3y=-24
y=8

7y+19=10y-5
-3y=-24
y=8

ABD=32+7=39
DBC=24+12=36
ABC=75 degrees