Question

The measure of angle ABD is represented by 4y+7.
The measure of angle DBC is represented by 3y+12.
The measure of angle ABC is represented by 10y-5.

Answer 1

Therefore, when you sub in the values for each angle, you get:

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

With a little algebra, you get:

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

Now that you have y, you can go back and substitute into the original expressions given for each angle.

ABD = 4y+ 7 = 4 (8) + 7 = 39
DBC = 3y + 12 = 3 (8) + 12 = 36
ABC = 10y - 5 = 10 (8) - 5 = 75.

You can do a check as well, to make sure it works.

Left Side Right Side

= ABC = ABD + DBC
= 75 = 39 + 36
= 75 = 75

"Left side equals right side, therefore, the solution is correct."

Answer 2

ok big help.