Solve by substitution

3x - 3y = - 6

z=-3x-3y+9

-4x+5y+z=8

Combine the radicals 5√27 - 17√3

If there are 4 quarts in a gallon, and 2 pints in a quart, and 2 cups in a pint, then how many cups are in a gallon?

What prime factor (s) will make the lcm of 9 and 15

Vincent spent a total of 1 1/4 hours at the trampoline park if he spends 3/4 of an hour eating birthday cake, and the rest of the time doing flips ... How much time is he flipping?

A plane flew from New York to Florida which was 1,259 miles one way. If the plane made 6 trips how many miles did the plane travel altogether?

A basket of beads contains eight red beads six yellow beads and six green beads. A bead will be drawn from the basket and replaced 150 times. What is a reasonable prediction for the number of times a green bead is drawn?

How many different 10-letter code words can be constructed from the English alphabet?

The circumference of a circle with a radius of 2 meters is approximate by the perimeter of an inscribed polygon with 10 sides. Which expression gives the described approximation of the circumference?

2x^2-16+22=0 (quadratics)

In ΔABC, AB = 20 cm, AC = 15 cm. The length of the altitude AN is 12 cm. Prove that ΔABC is a right triangle.