What is the variable in the expression: 3x + 4

Find the vertex of the function given below y=x^2-6x+1

What is the equation of a vertical line passing through the point (−5, −1)? y = −5 y = −1 x = −5 x = −1

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?