PLEASE HELPP WILL MARK BRAINLIEST! ABCD is a rectangle. If AC=x+12 and BD=4x−3, find the value of x. Round to the nearest whole number if necessary.

Find the length of EC. Round to the nearest tenth if necessary.

EC =

How do you use the elimination method for this question? explain, because i really want to understand!

Use circumcenter theorem to solve for the given values

Which statements describe the solutions to the inequality x< -20 check all that apply. there are infinite solutions. each solution is negative. each solution is positive. the solutions are both positive and negative. the solutions contain only integer values. the solutions contain rational number values.