A triangle has side lengths of (4.5x + 7.5y)cm, (8.4x +2.5z) cm, and (1.5z - 4.5y) cm. Which expression represents the perimeter, in centimeters, of the triangle? 1) 19.9xyz
2) 12xy + 10.9.xz - 3yz
3) 12.9x + 3y + 4z
4) 12.9x - 12y + 4z

Prove that the sum of two consecutive exponents of the number 5 is divisible by 30.if two consecutive exponents are 5n and 5n + 1, then their sum can be written as 30.

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a. m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

Order the measurements from the least to the greatest. 2,720 ml , 24.91 l , 0.0268 kl