Answer:
-4r - 11 = 4r + 21
-4r -4r = 21 + 11
-8 = 32 (Divide both sides by -8)
/ /
-8 -8
= -4
Answer:
Step-by-step explanation:
(2n - 3)(5n + 6) = 2n*(5n + 6) -3*(5n +6)
=2n*5n + 2n*6 -3*5n + (-3)*6
=10n² + 12n - 15n - 18
= 10n² -3n - 18
180
Explanation:
Set a equation of a ratio 120/90=x/135
And calculate!
90x=(120)(135)
90x=16200
x=180
A collection of nickels and dimes is worth $4.40. There are 53 coins in all. How many nickels are there?
Nickel is a US coin worth 5 cents or 0.05.
Dime is a US coin worth 10 cents or 0.10
n + d = 53
0.05n + 0.10d = 4.40
n = 53 - d
0.05(53 - d) + 0.10d = 4.40
2.65 - 0.05d + 0.10d = 4.40
0.05d = 4.40 - 2.65
0.05d = 1.75
d = 1.75 / 0.05
d = 35
n = 53 - d
n = 53 - 35
n = 18
There are 18 nickels and 35 dimes.
0.05n + 0.10d = 4.40
0.05(18) + 0.10(35) = 4.40
0.90 + 3.5 = 4.40
4.40 = 4.40
Surface area of a square pyramid is the area of the base + 4 times the area of one of the slanted sides.
Area of base = side length * side length
Area of side = (1/2) * side length * slant height
Don't forget that you have to multiply the area of the side by 4!
Step 1: 12 x 12 = 144
Step 2: 12 x 20 = 240 divided by 2 = 120
Step 3: 144 + 120 x 4
