How do I solve this system using substitution: y = x + 4; y = 3x

Can someone simplify 25-4-9x+2x?

Write a story problem that includes 8 and 12

Find two consecutive whole numbers that 102 lies between.

Corey and Devante both leave the park at the same time but in opposite directions if Corry travels 30 mph and Devonta travels 22 mph how long until they're 105 miles apart

Fractions in simplest form have the denominator with terminating decimals; fractions with denominators of 6, 12, 18, and 24 produce repeating decimals. What is the difference?

What is the probability that two people selected at random have the same birthday? Ignore leap years. 1/365 2/365 1/133,225

F (x) = 10x 5 and g (x) = 3x 6 then what is (f-g)

A rectangular prism has a height of 3, a length of 4, and a width of 12, what is the surface area?

Randy is building a rectangular, fenced dog run beside his barn. He has 120m if fencing and plans to use the side of the barn as one side of fenced area. What are the dimensions of a dog run that maximizes the area Randy can enclose

The projection screen in the school auditorium is five times as long and 5 times as wide as the screen in the library. The screen in the library is 4 feet long with a perimeter of 14 feet. what is the perimeter of the screen in the auditorium?