Using the triangle, we can find the angle lengths and using those and trig ratios, find the side lengths. Lets say the top side length is "y".
Using the Law of triangles, we can find the missing angle from 180-90-70=20 deg.
Then we can use the Law of sines,
sin(70)/13=sin(20)/y
y=sin(20)*13/sin(70)
y=15.34
Finally, we use the Pythagorean Theorem, (13)^2+(15.34)^2=x^2
x = 20.1
So the expression is:

You can combine like terms, which are terms that contain the same variables raised to the same power. That means you can combine the two

.

The other terms can't be combined.
Your final answer should be

.
Step-by-step explanation:
and
are linear pair angles.

Answer:
Firstly, rewrite the equation:
⅓ (18 + 27) = 81
Substitute x for the given number of it's supposed equivalent.
In this case x = 12.
⅓ (18(12) + 27) = 81
Solve using PEMDAS and simplify what is in the parenthesis first. Then, multiply.
(18 x 12) + 27 = 243
Now, solving using PEMDAS, multiply the total of what you got that was originally in the parenthesis by ⅓ .
⅓ (243) = 81
When you multiple these number they are equivalent to 81.
81 = 81
Since the equation given, when substituted x for 12, is equivalent to 81, this proves that substituting x for 12 makes this equation true.
Multiply the bracket by 5
I used PEMDAS
P= parenthesis
E= exponents
M=multiplication
D= division
A= addition
S= subtraction
7r+2= 5(r-4)
7r+2= 5r-20
Move 5r to the left hand side . Positive 5r changes to negative 5r
7r-5r+2= 5r-5r-20
2r+2=- 20
2r+2-2= -20-2
Move positive 2 to the right hand side. Changes to negative -2
2r+2-2= -20-2
2r= -22
Divide by 2 for 2r and -22
2r/2= -22/2
r= -11
Answer is r= -11