Please help me i need help with this math quion

Which equation represents a proportional relationship that has a constant of proportionality equal to 1/5

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.

What is the simplified form of square root of 400 to the 100th power ?