Solve the system of equations using matrices. use gaussian-jordan elimination.
6) 7x - y + 2z = 21
9x - 3z = 0
3y + z = 21

Rewrite the following quadratic functions in intercept or factored form. show your work. y = 9 + 12x + 4x^2

The number of chocolate chips in a bag of chocolate chip cookies is approximately normally distributed with a mean of 12611261 chips and a standard deviation of 118118 chips. (a) determine the 2626th percentile for the number of chocolate chips in a bag. (b) determine the number of chocolate chips in a bag that make up the middle 9696% of bags. (c) what is the interquartile range of the number of chocolate chips in a bag of chocolate chip cookies?

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25