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:
A
Step-by-step explanation:
A is the less complicated one and the simplest but also the most efficient and the one that makes the most sense.
For 1 multiply both sides by 3 which gives you 3y-y=12. Then combine like terms 2y=12. Lastly divide both sides by 2 and you get y=6. And for 3 first multiply both sides by 4 which gives you 6y-32=y+8. After that combine like terms 6y-y-32=8. Now add the equation together 5y=40 and then divide by 5 and get y=8
17 11 9 and 7
Remember that the third side must be greater than 5 and less than 19.
