How to solve 2x+y=8 and 2x-3y=24 by substitution

When you have 25 numbers, and jake picks 3 random numbers and puts them back, what is the chance bob has of picking those 3 numbers when he picks 6 random numbers (without putting them back)? explain.

When a valve is open 281 gallons of water go through it in one hour the number of gallons that would go through in 94 hours is

Which is an x-intercept of the graphed function? (0, 4) (–1, 0) (4, 0) (0, –1)