Answer:
√841
Step-by-step explanation:
You would use pythagorean theorem to solve this problem:
a² + b² = c²
a = 20 b = 21
20² + 21² = 400 + 441 = 841
√841
B, D, A
No problem make sure to heart my comment Helps
Part 1)
we have
------> equation A
------> equation B
Multiply by
the equation A
------> equation C
Multiply by
the equation B

-------> equation D
Adds equation C and equation D

therefore
<u>the answer Part 1) is the option A </u>

Part 2)
we have
------> equation A

Simplify Divide by
both sides

------> equation B
the lines A and B are parallel lines, because the slope m is equal
so
The system has no solution
therefore
<u>the answer Part 2) is the option D</u>
There is no x value as there is no solution to the system.
Part 3)
we have
------> equation A

------> equation B
substitute equation B in equation A
![4x+2[x-3]=6](https://tex.z-dn.net/?f=4x%2B2%5Bx-3%5D%3D6)



therefore
<u>the answer part 3) is the option D</u>

Part 4)
Let
x---------> The number of one-step equations
y---------> The number of two-step equations
we know that

-------> equation A
------> equation B
substitute equation A in equation B
![3[1,120-y]-2y=1,300](https://tex.z-dn.net/?f=3%5B1%2C120-y%5D-2y%3D1%2C300)




therefore
<u>the answer part 4) is the option D</u>

Answer:
<em>summation of five times negative three to the power of n from n equals zero to infinity</em>
Step-by-step explanation:
<u>Summation Notation
</u>
It represents the sum of a finite or infinite number of terms. Let's analyze the terms of the given succession:
5-15+45-135+...
If we take 5 as a common factor, we have
5(1-3+9-27+...)
The parentheses contain the alternate sum/subtraction of powers of 3. The odd terms are positive, the even terms are negative, thus the exponent must be n starting from 0 or n-1 starting from 1
The summation is then represented by

This corresponds with the option:
<u>summation of five times negative three to the power of n from n equals zero to infinity</u>