Is (5, 4) a solution to this system of equations?

2x + 3y = 23

y + x = 9

In a sale, the price of a computer is reduced by $113. The sale price is $1227. Find the marked price (original price) and the rate of discount. Round the discount rate to the nearest tenth of a percent if necessary.

Round the fraction to the nearest whole number. 5 2/7

A group of friends ordered two pizzas, one with pepperoni and one with mushrooms and green peppers. A plain pizza costs $9. Each topping costs $1. How much did the two pizzas cost?

Change the fraction to a percent 3/20

Kaci was trying to figure out how many pounds of Havarti cheese she could buy for $10, knowing that 3 pounds costs $7.50.

Is 6/10 equal to 4/7

What is the minimum value of P=24x + 30y given the constraints

The cylinder shown has a volume of 54π cm3. In a similar cylinder, the dimensions have been doubled. What is the ratio of the volumes (small to large) ?

A sequence is defined that the first term is 4 and each term after the first term is found by adding 4/5 to the preceding term. What is the 8th term of the sequence?

A scientist is investigating a cell. The cell has a membrane thickness of 7.*10-8 m and has a surface area of 4.*10-8. The initial concentration inside the cell is n (0) = 0.6 M, and the scientist later observes that an (0.2) = 0.77 M.