9x + 3 = 7x + 19 me and show the steps to how you got your answer

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.

What is the value of x? assume that the line is tangent to the circle.

Which of these figures must be a rectangle?