MTH 119 โ Spring โ 2005
Essex County College โ Division of Mathematics
Quiz # 31โ February 1, 2005
Name:
Signature:
Show all work clearly and in order, and box your final answers. Justify your answers algebraically
whenever possible. You have 20 minutes to take this 10 point quiz. When you do use your
calculator, sketch all relevant graphs and write down all relevant mathematics.
1. Use Cramerโs rule to solve the following system.
๎3xโ2y= 5
5x+ 4y= 12
x=๎
๎
๎
๎
5โ2
12 4 ๎
๎
๎
๎
๎
๎
๎
๎
3โ2
5 4 ๎
๎
๎
๎
=44
22 = 2 = x , y =๎
๎
๎
๎
3 5
5 12 ๎
๎
๎
๎
๎
๎
๎
๎
3โ2
5 4 ๎
๎
๎
๎
=11
22 =1
2=y
2. Find the area of the triangle with vertices (0,โ1), (2,0) and (3,7).
A=ยฑ1
2๎
๎
๎
๎
๎
๎
0โ1 1
2 0 1
3 7 1
๎
๎
๎
๎
๎
๎
=ยฑ1
2[0 + 1 (2 โ3) + 1(14 โ0)] = ยฑ13
2
The area is 13
2= 61
2.
1This document was prepared by Ron Bannon using L
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