MATH 31 Sp16 Instr: H. Lan CH3&4
Name__________________________________
Directions: Show ALL work in the space provided NOT on the scratch paper. Closed books and
notes. No calculator is allowed. Circle or otherwise indicate your final answers.
____________________________________________________________________________
__
• Good luck! :)
1.
Perform the indicated operations:
− 12 − 2 [18 − (8 − 9)]
2.
Solve A = P +Prt for r.
3.
Solve for the equation 0.1(x − 3) = 1.1 − 0.25x
4.
80 is 15% of what?
5.
Find the x-intercept of the graph of
3x − 5y = 30.
6.
Find the linear equation of the line passing the points (− 1, 2) and (− 3,− 4), and then
write the equation in ​slope-intercept​ form.
7.
Write an equation in standard form when the slope of the the line is − 3 , and the line
passing through ( − 1, 5 ).
8.
Graph the line on the plane below whose equation is 2x + y = 0.
11.
Graph the inequality y < − 3x + 2.
12. Determine(no graphing) whether the lines through the points are parallel, perpendicular, or
neither.
(2,4) and (6,1); ( − 3,1) and (1, − 2).
13. Graph x ≤− 2
14.
Determine whether (200, 700) is a solution of the system
− 4x + y = − 100
0.05x − 0.06y = 32
15.
Solve the following system by ​addition​ method.
4x + 5y = 3
2x − 3y = 7
16. Solve the following system by ​graphing.
x+y = 6
4x − y = 4
17.
Solve the following system by ​substitution​ method.
6x+2y=7
3x+y=2
18.
Solve the system of linear equations (any method).
4x = 36 + 8y
3x − 6y = 27
19.
Solve the system of linear inequalities on the plane below.
x + 5​y ​<​ 10
x>0
20.
a) Determine whether the ordered pair (-2, 1) is a solution of 4x-2y=10
b) Determine whether the ordered pair (-2, -5) is a solution of 3x-4y>7.
21. How many ounces of a 50% alcohol solution must be mixed with 80 ounces of a 20%
alcohol solution to make a 40% alcohol solution?
22. You invested $14,000 in two funds paying 7% and 9% interest. Total year-end interest was
$1180. How much was invested at each rate?
23. Three times a first number decreased by a second number is − 1. The first number increased
by twice the second number is 23. Find the numbers.
24. Find the slope of each equation:
a) y= − 2
b) 2x − 3y=6
25. Extra credit(4pts, no partial credit will be given): Write an equation(any) for a line that is
parallel to 3x − 7y = 15, and another equation for a line that is perpendicular to 3x − 7y = 15.