A cookbook originally cost $13.00. Yesterday, Marta bought it at 40% off. How much was deducted from the original price?

$0.40

$4.20

$5.20

$7.80

What is the area of a triangle with vertices at (-3 3) (-3,2) and (1,2)?

Which of the following equations is equivalent to x/3-6/x=1

Betty correctly answers 30 questions on your math test there are 40 questions on the test what percent of the questions did she answered incorrectly