Math 125 Test 3 F/96 (8 pt

Sample Math 123b Test 3

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0. Problem 1-6 on sample 2.

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1. Gra= ph the following x&y equations. = Label at least 2 points on the graph. Find the x, y intercepts if there is any.

a. 3x – 2y =3D12 = b. 2y – 5 =3D0 c. 3y =3D 7 = d. 2x + 5 =3D 0 = d. 3x + 4y =3D 24 =

2. Find the slope of each of the following line.

a. The line passes (3, –4) and (–1, R= 11;7) = b. The line passes (2, –1/3 )= and (–2, 3/2) =

c. The line passes (–3, –2) and (–= 1, 4) &nbs= p;

d. The line passes with the x intercept at x=3D2, and y-intercept at y =3D –5. =

e. The equation of the line is 3x =3D –5y+7

f. The equation of the line is 0 =3D –5y+7 = g. The equation of the= line is 3x =3D +7

h. It is parallel to 2y =3D 5 – 6x = &nb= sp; = i. It is perpendicular 2y= =3D 5 – 6x

Ans: a. ¾ b. –11/24 c. 3 d. 5/2 e. –3/5 f. 0 g. UDF &nb= sp; h. –3 i. 1/3

3. Find the equations of the lines that

a. pas= ses (3, –4) and (–1, –7) b. (2, –1/2 ) and (–1/2, ¾ ) c. (3, –4) and (= 3, 7)

Ans: a. 4y =3D 3x – 25 b. 2y =3D –= ;x + 1 c. <= span style=3D'mso-spacerun:yes'> x =3D 3

4. Find the equations of the lines that

a. has x-intercept at 2 and y–intercept at –5 b. has y–int at –= ;3 and no x-intercept

a. 2y =3D 5x – 10 = b. y =3D –3

5. Find the equations of the lines that pass through= (4, –1) and parallel to

a. 2y – x =3D 6 b. the line that passes through (2, –4) and (–2, –3) c. the x-axis

Ans: a. 2y =3D x – 6 = b. 4y =3D –x –14 = c. y =3D –1 =

6. Find the equations of the lines that pass through= (–3, 3) and perpendicular to

a. 2y – x =3D 6 b. the line that passes through (2, –4) and (–2, –3) c. the y-axis

a. y =3D –2x – 3 b. y =3D 4= x + 15 = c. x =3D –3=

7. Estim= ate the slope of the following line then find the equation the line.

Ans: Use= the point (0, 4), (–6, 0) we get m ≈ 2/3 and 3y =3D 2x + 12

8. A machine depreciates linearly. It is worth $4,500 after 2 years a= nd $3,900 after 4 years. Find the equation of the values after x years. How much is it worth after 9 years?= Ans: y =3D $, x =3D nu= mber of years y =3D –300x= + 5100, after 9 years y =3D 2400

9. For his long dista= nce calls, Joe pays a base price plus minutes used per month. If for Jan. the total long distanc= e charge was $11.30 for 80 minutes of calls and for Feb. it was $10.40 for 50 minute= s of calls. How much is the charge= for March if he made 100 min. of long distance calls?

Ans: y =3D $ in cents, x =3Dnumber of min. y =3D 3x + 890, he paid $11.90 for= March