Solve the equation x=4/3(pie)r3 for r

I’m stuck on this equation, anyone got the answer?

Type the correct answer in the box. consider the system of linear equations below. rewrite one of the two equations above in the form ax + by = c, where a, b, and c are constants, so that the sum of the new equation and the unchanged equation from the original system results in an equation in one variable.

Erik buys 2.5 pounds of cashews. if each pound of cashews costs $7.70, how much will he pay for the cashews?