20 Answer: a₁ = 4
<u>Step-by-step explanation:</u>

21 Answer: n = 13
<u>Step-by-step explanation:</u>

22 Answer: n = 5
<u>Step-by-step explanation:</u>

Answer:
Ax+By=C and 7.5 lb of Thistle
Step-by-step explanation:
Answer:
The set of all points on a plane equidistant to a given point
Step-by-step explanation:
"following"?
Answer:
<ADC=131°
Step-by-step explanation:
<ADC= <ADB+<BDC
We need to substitute the angle measures and simplify to get:
<ADC=89+42
This simplifies to give us:

The correct answer from the given options is the first choice.