Solve the system of equations using matrices. Use Gaussian-Jordan elimination.

6) 7x - y + 2z = 21

9x - 3z = 0

3y + z = 21

What is the area 17 x 17

Write an expression for "c plus 2."

1222+56660+900+10+100+21

What is the sample space for flipping a coin and rolling a die?

Is x+1 a factor of the polynomial 12x^4+5x^3+3x^2-5? Explain your answer.

How to find number of sides from sum of interior angles?

What is 950,000,000 in scientific notation?

6,8,10,12 arithmetic or geometric

There is a number, which has five digits 5abc9. If this number is the square of an integer, where a, b, c each represent a missing digit and all five digits are different, then find this number.

Andy's backpack weighs 2 1⁄4 pounds. If he removes a book that weighs 13 ounces, how much does the backpack now weigh?