Solve the system of equations x + y = 4 and -9x + 7y = -84 by combining the equations.

If you prove that ∆wxz is congruent to ∆yzx, which general statement best describes what you have proved?

The coverage of a base station of a telecommunication company forms a disk with a radius of (kilometers). let be the distance of a cellphone from a base station. assume that the location of cellphones in use are randomly uniformly distributed within the disk. calculate the mean and variance for the random variable.

Given a normal distribution with µ=20 and σ = 4, what is the probability that x> 24 x< 24 x< 24 or x> 24