Answer:
C
Step-by-step explanation:
Option C is the only one that's linear because it follows all of the rules for a line to be linear. To check, use the process of elimination:
A). When x is an absolute value, the line will not be linear because an input will have two outputs.
B). x cannot be in the denominator of a fraction for the line to be linear
D). Once again, x cannot be an absolute value.
*Note: I'm assuming in option B, 7x is in the denominator and 1 is in the numerator. If the fraction is simply 1/7 multiplied by x, it is linear along with C.
The value of the missing length is 20
Let the missing length be x
From Parallel lines and transversal theorem, we have that
If three or more parallel lines intersect two transversals, then they cut off the transversals proportionally.
Then, we can write that

∴ 
x = 20
Hence, the value of the missing length is 20
Learn more here: brainly.com/question/24258397
This is a pretty complex problem
Answer:
21) 12 cm
22) 5.9 cm
Step-by-step explanation:
21) The base is 10, and if the other two sides are congruent and the perimeter is 36, we can figure out with simple algebra that the sides are 13 cm long.
Half of 10 is 5, so we can use the pythagorean theorem.
5^2+x^2=13^2
Rearranging the variables we have 169-25=x^2
144=x^2
x can be plus or minus 12, but since negative length is impossible we find that x is positive 12 cm.
22) We want to use sine, because we have opposite and hypotenuse. A simple and easy way to memorize this is the SohCahToa method. If we have opposite (O) and hypotenuse (H) we have OH. Soh has the letters O and H, and the S means we should use sine.
sine 36=a/10
Plug this into a calculator or desmos scientific calculator to get a=5.9