Help please. i will give brainliest​

What is the standard form of -5x^2+2x^4-11+x^3+3x

The length of a rectangle is x times the square root of 100. the width is one-half y more than three-halves x. given that the area of the rectangle is 125 cm2, which equation could represent the rectangle in terms of x and y? a) 5xy − 15x = 125 b) 5xy + 15x = 125 c) 15x2 − 5xy = 125 d) 15x2 + 5xy = 125

Yvaries inversely as x. y =12 when x=5. find y when x=4