Juanita begins to factor an expression as shown.

x2 + 3x – 18 = (x + )(x – )

the numbers that should be placed in the boxes, from left to right, are
.

6 and 3. To find this answer, you simply need to factor the expression on the left-hand side of the equals sign. To factor the expression, you need to find 2 numbers which add up to be 3 and multiply to be -18. The two numbers which do this are 6 and -3. Since you want a positive 3, you know that the 6 goes in the left box and the 3 goes in the right box.

The answer would be 13.5 minutes.