Yo i need help please i need the correct answer i will give u a brainliest to please just help me

Select the correct answer from each drop-down menu. a system of equations and its solution are given below. system a complete the sentences to explain what steps were followed to obtain the system of equations below. system b to get system b, the equation in system a was replaced by the sum of that equation and times the equation. the solution to system b the same as the solution to system a.]

Write as a product: ac^2–ad+c^3–cd–bc^2+bd

Given: m zade = 60° and m2cdf = (3x + 15) prove: x = 15