Create an equivalent system of equations using the sum of the system and the first equation. −5x + 4y = 8 4x + y = 2 −5x + 4y = 8 9x + 5y = 10 −5x + 4y = 8 −x + 5y = 10 −5x + 4y = 8 9x + 5y = 2 −5x + 4y = 8 −x + y = 10

Geometry ? i don't know how to do any of these.

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

The length of a shadow of the building is 36m. the length of the pole, which is perpendicular to the ground, is 1.9m. the length of the pole's shadow is 1.52m. what is the height of the building?