Find m∠R. This is math homework

Question

In ΔRST, m∠R=(5x−11)∘, m∠S=(3x−3)∘, and m∠T=(3x+18)∘. Find m∠R.

Answer 1

The 3 angles of a triangle will always add up to equal 180 degrees.

So as long as you only have one variable, you can solve.

Your equation is R+S+T=180

Now, just put in the information they give you:

R is 5x−11,

S= 3x−3, and 

T= 3x+18

5x-11+3x-3+3x+18=180

R + S + T =180

Next, combine like terms.

you can combine 5x+3x+3x to equal 11x, and

combine -11-3+18 to equal 4.

So, 11x+4=180

subtract 4 from both sides to start isolating the variable x

11x=176

since 11x means 11 times x, we dived by 11 on both sides to get x by itself.

on the left, when we divide by 11, we cancel it out, and get x alone.

x= 176 divided by 11,

x= 16

You can double check your answer by substituting the number 16 wherever you have an x in the equation

5x-11+3x-3+3x+18=180.

Remember, 3x means 3 times x.

so (5 times 16)-11+(3 times 16)-3+(3 times 16)+18=180

80-11+48-3+48+18=180

check!

Answer 2

The sum of the measures of the interior angles of a triangle is 180 so

m<R + m<S + M<T = 180

substitute expressions for the measures of the above angles into the equation and solve for x:

5x - 11 + 3x - 3 + 3x + 18 = 180

11x + 26 = 180

11x = 154

x = 14

m<R = 5x - 11 = 5(14) - 11 = 59