SAT Review 1.Which is the equation of a line that passes through the pt (7, - 1) and is to y + 2x = 1. A. y = 2x – 15 B. y = –2x + 13 C. D. 2.Line p is parallel to line m, x˚- y˚=? A. 0 B. 50 C. 80 D ˚ x˚ y˚

( ) =100, which ends in a zero so it is valid 3( ) =82, which ends in a 2 so it is invalid If someone mad a single-digit error, can you tell which digit is incorrect? NO

Change one digit in this invalid number s the resulting number is valid. Several answers are possible… Determine the check digit for the UPC number d 3( ) d 69 + d, since the number must end in a zero to be valid…69 + d = 70 So d = 1.

4.Suppose you entered 8 instead of 9 when recording the UPC number The difference between 3(9) – 3(8) = 3, so the sum of the weighted sum of the digits in the invalid number cannot end in 0.

Determine if the UPC code is valid Find the value of the check digit that will make the UPC code valid d d 5. Come up with 2 valid UPC codes of your own. 6. Check out 2 real UPC codes and see if they are valid under our formula.