What is the measure of angle a in the triangle?
m∠a = °

180° = 70° + (2x-10°) + (x+30°)
180° - 70° = (2x-10°) + (x+30°)
110° = 3x + 20°
110° - 20° = 3x
90° = 3x
x = 30°
A is 2x - 10°
A = 2(30) - 10
A = 60 - 10
A = 50°

The answer is 50 degrees. So, triangles add up to 180 degrees, so :  (2x - 10) + x + 30 + 70 = 180 degrees. You add like terms first to solve what x equals first. we can combine 2x and just a plain x, and that is 3x. So now, it is more simplified. It is now 3x -10 +30 +70. Now you add 70 + 30 - 10. That will get you 90 so now it is easily simplified to 3x = 90. To get x by itself, divide 3x by 3 and that will lead you with x by itself. If you divide by 3 to that side, you have to do it to the other side. So 90 divided by 3 will get you 30, so therefore x=30. Now if you want to solve for measure angle A, plug in 30 for x instead now. Like this : 2{30} - 10, multiply 30 to 2 and you get 60, then subtract 10 and the answer is 50.