How will i solve this can someone explain? (i suck at geometry i change my answer constantly)

What is the value of 1/3x + 7x when x = 5

Students are given 3 minutes to complete each multiple-choice question on a test and 8 minutes for each free-responsequestion. there are 15 questions on the test and the students have been given 55 minutes to complete itwhich value could replace x in the table? 5507-m23-m8(15-m)8(15)-m

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?