-40 over 100, is the answer
3x - 7
The perimeter is the sum of all 3 sides of the triangle
To find the third side subtract the sum of the 2 known sides from the perimeter
x + 3 + 2x + 4 = 3x + 7
third side = 6x - (3x + 7 ) = 6x - 3x - 7 = 3x - 7
I think they should say they last name
No . but she can buy 2 of the books but not all 3