The perimeter of a triangle is (x 3 + 2x
2 − x − 1) cm. The lengths of two sides are

(7x
3 + 12x − 7) cm and (2x
3 − 3x
2 + 5x − 11) cm. Find the length of the remaining side of

the triangle.

How many liters of peroxide should be added to 12 liters of an 8% peroxide solution so that the resulting solution contains 16% peroxide?   original added new amount of peroxide 0.96 liters x 0.96 + x amount of solution 12 liters x 12 + x 0.18 liter 1.14 liters 1.92 liters 2.10 liters