Rewrite the expression by combining like terms.
3x^2 + y + 2y^2 + 4y^2

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

Prove the divisibility of the following numbers: 25^9 + 5^7 is divisible by 30.also, read as (25 to the power of 9) + (5 to the power of 7) is divisible by 30. blank x 30what is the blank? ( it should be expressed in exponent form)

Aswimming pool had 2.5 million liters of water in it. some water evaporated, and then the pool only had 22 million liters of water in it. what percent of the water evaporated?