9. Read the following word problem, then create a linear equation to model the problem. Provide work to show how your linear equation models the problem, such as a brief description, a picture, or a table. Finally, use the linear equation you created to solve the problem. $2400 is divided between two accounts. One account pays 2% interest, while the other account pays 3.5% interest. At the end of one interest period, the interest earned is $81. How much was invested in each account?

10. Read the following word problem, then choose which linear equation models the problem.

The length of a rectangle is six feet more than twice the width. The rectangle’s perimeter is 84 feet. Find the width and length of the rectangle.
A. 2w + 6 + w = 84
B. 2(2w + 6) + 2w = 84
C. 2(2w +6) • (2w) = 84
D. (2w + 6) • (w) = 84

11. Read the following word problem, then choose which linear equation models the problem.

The sum of the ages of an older sibling and a younger sibling is 16. Four years from now, the age of the younger sibling will be the same as the age of the older sibling was two years ago. Find the present age of each sibling.
A. x - 4 = 14 + x
B. 4x = 14 - x + 16
C. x + 14 - x = 16 + 2
D. x + 4 = 14 - x

16. Jessica was given the area and the length of the base of a triangle. A = 17.5 units, b = 5 units. She solved the formula for area for h to find the height of the triangle. Determine if Jessica solved the equation correctly and found the correct answer. If not, describe what mistake she made and solve the formula for h correctly and justify your steps.

A = 1/2bh
1/2A • b = h
1/2 (17.5)(5) = h
43.75 = h

The height of the triangle is 43.75 units.