Answer: Todd used 27 black tiles.
Step-by-step explanation:
Let x represent the number of black tiles that Todd used.
Todd uses 21 white tiles & some black tiles to make a mosaic. This means that the total number of white and black tiles that Todd used is 21 + x
Each tile has an area of 3 square centimeters. This means that the total area covered by the white tiles is
21 × 3 = 63 square centimeters
Also, the total area covered by the black tiles is
3 × x = 3x square centimeters
The mosaic has a total area of 144 square centimeters. This means that
3x + 63 = 144
3x = 144 - 63
3x = 81
x = 81/3 = 27
Answer:
6 : 1
Step-by-step explanation:
b - 3a / 9 = a /3
Cross multiply
3(b - 3a) = 9a
Expand
3b - 9a = 9a
Add 9a to both sides
3b = 9a + 9a
3b = 18a
Divide both sides by 3
b = 6a
Ratio of a : b
6 : 1
Answer:
Step-by-step explanation:
-2x -3y = 5
4x + 3y = 17
2x = 22
x = 11
4(2) + 3y = 17
8 + 3y = 17
3y = 9
y = 3
(11,3)
Answer:
$125
Step-by-step explanation:
if there was a discount of 20%, the sales price is 100 - 20 = 80% of the original price
let a = original price
this equation can be used to represent the question
a x 0.8 = 100 ]]divide both sides by 0.8
a = 100 / 0.8 = 125
Answer:
X= -7/6, 17/8
Step-by-step explanation:
Foil it, then use quadratic to find zeros/roots.
