Please someone help it’s due in an hour!

What signals you that factoring by grouping is the best method to use when factoring a problem?

Let the closed interval [a , b] be the domain of function f. the domain of f(x - 3) is given by (a) the open interval (a , b) (b) the closed interval [a , b] (c) the closed interval [a - 3 , b - 3] (d) the closed interval [a + 3 , b + 3]

The measure of an angle is 117°. what is the measure of a supplementary angle?