(50 POINTS) I'm in need of assistance- A portion of the Quadratic Formula proof is shown. Fill in the missing reason. A. Rewrite the perfect square trinomial as a binomial squared on the left side of the equation

B. Take the square root of both sides of the equation

C. Multiply both sides of the equation by 2

D. Square the left side of the equation

7x+8y=-18, 4x-9y=-3 solve the system of equations

Steve wants to develop a way to find the total cost of any item including sales tax. the sales tax in his city is 6%. his friend jenna writes the expression x + 6x where x is the cost of the item. explain whether her expression is correct based on the situation.

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?