Fill in the blank with a number to make the expression a perfect square x^2+ 4x + ?​

If 20% of a number is 35, what is 50% of that number?

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

Given the system of equations presented here: 2x + 4y = 14 4x + y = 20 which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? multiply the second equation by â’4 to get â’16x â’ 4y = â’80 multiply the second equation by â’1 to get â’4x â’ y = â’20 multiply the first equation by 2 to get 4x + 8y = 28 multiply the first equation by â’1 to get â’2x â’ 4y = â’14