Answer:
a. =11+ 1
b. =4x+ (-7y) + (-5z) +6
c. (-3x) + (-8y) +(-4)+(-8/7z)
Step-by-step explanation:
a. 20 - 9 + 8 -7
=11+ 1 ( this is obtained by solving)
b. 4x - 7y - 5z + 6
=4x+ (-7y) + (-5z) +6
We multiply the negative sign with the positive sign to get a minus so the answer remains the same and the expression is written as an addition sum.
c. -3x - 8y - 4 - 8/7z
-[ 3x+8y+4+8/7z]
or
(-3x) + (-8y) +(-4) +(-8/7z)
The minus sign is taken as common leaving the expression with the plus only.
It can be written in the same manner as above, adding the negative terms so that the expression is written as a sum.
The new pool is 18.84 feet larger in circumference than the old one.
<u>Explanation:</u>
Given:
Circumference of the pool = 47.1 feet
Diameter of the new pool, d = 21 feet
radius, r = 21/2 feet
Circumference of the new pool = ?
We know:
Circumference = 2πr
where,
r is the radius
On substituting the value:
C = 
C = 65.94 feet
The difference in circumference of the two pools = 65.94 - 47.1 feet
= 18.84 feet
Therefore, the new pool is 18.84 feet larger in circumference than the old one.
D the rest would be impossible to recreate