Frank is going to plant x vegetable seeds in one garden and 3x+7 vegetable seeds in another. How many seeds is Frank going to​ plant?

This is so hard and it’s for a test

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)

How many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.) how many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.)