X^2 = 7^2 - 3^2
x = root40
3.5x-10>-3 add 10 to both sides
3.5x>7 divide both sides by 3.5
x>2
... now for the other inequality:
8x-9<39 add 9 to both sides
8x<48 divide both sides by 3
x<6
So we have x>2 and x<6, so the compound inequality is:
2<x<6 and this means that the solution set is:
x=(2, 6)
Using google translate:
When photocopying a credential, it is first enlarged to triple and subsequently the resulting copy is halved. What is the final effect on the original credential? If the credentials is a rectangle of 10 by 6 cm. What area will you have in the first photocopy? And in the second?
Original: 10 by 6 cm ; Area = length * width = 10 x 6 = 60 cm²
first copy: enlarged to triple
10 x 3 = 30
6 x 3 = 18
30 x 18 = 540 cm²
second copy: halved
30 x 1/2 = 15
18 x 1/2 = 9
15 x 9 = 135 cm²
