If 3 is underline in 315, what is the value of the underlined digit

Before simplifying, how many terms are there in the expression 2x - 5y + 3 + x?

Write a function for a rotation 90 degrees counter clockwise about the origin, point 0

21 type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar. the solution set of n2 - 14n = -45 is { (separate the solutions with a comma)