What substitution should be used to rewrite 4x^4-21x^2+20=0 as a quadratic equation

Jack lives on a farm and has a large backyard. the area of his rectangular backyard is of a square mile. if the width of the yard is of a mile, what fraction of a mile is the length of the rectangular backyard?

Which of the following describes how to translate the graph y = xi to obtain the graph of y = x - 11 - 12 1 unit left and 1 unit down 1 unit left and 1 unit up 1 unit right and 1 unit down 1 unit right and 1 unit up

Can someone me with this problem . show your work .