# Alg homework. Help. 10 pts best answer?

1. (3, 4);m = -
y – 4 = -(x – 3)
y + 4 = -(x – 3)
y – 4 = (x – 3)
y – 4 = -(x + 3)
2. (0, -3); m = 18
y – 3 = 18x
y – 3 = -18x
y + 3 = 18x
y + 3 = -18x
3. (-7, -5); m = 0
y + 5 = x + 7
y – 5 = 0
x = -7
y = -5
4. Write an equation for the line through the points (2, -6) and (-1, -4).
y –...
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1. (3, 4);m = -

y – 4 = -(x – 3)

y + 4 = -(x – 3)

y – 4 = (x – 3)

y – 4 = -(x + 3)

2. (0, -3); m = 18

y – 3 = 18x

y – 3 = -18x

y + 3 = 18x

y + 3 = -18x

3. (-7, -5); m = 0

y + 5 = x + 7

y – 5 = 0

x = -7

y = -5

4. Write an equation for the line through the points (2, -6) and (-1, -4).

y – 6 = -(x – 2)

y + 6 = (x – 2)

y + 6 = -(x – 2)

y + 6 = -(x + 2)

Write an equation of the line that is parallel to the given line and that passes through the given point.

5. x + y = 3; (5, 4)

y – 4 = (x – 5)

y – 4 = -(x – 5)

y + 4 = -(x – 5)

y – 4 = -(x + 5)

6. 3x + 2y = 1; (-2, 6)

y + 6 = -(x + 2)

y – 6 = -(x – 2)

y – 6 = -(x + 2)

y – 6 = -(x + 2)

Write an equation of a line that is perpendicular to the given line and that passes through the given point.

7. y = -4x + 2; (0,2)

y – 2 = x

y – 2 = -x

y – 2 = 4x

y + 2 = x

8. y = x + 6; (-6, 2)

y – 2 = (x + 6)

y – 2 = -(x + 6)

y – 2 = -(x + 6)

y + 6 = -(x – 2)

For Exercises 1-5, solve each system using elimination.

1. 2x + 5y= 2

3x – 5y = 53

(11, 4)

(11, -4)

(5, 0)

(5, -10)

2. -8x – 3y = 69

8x + 7y = -65

(-9, 1)

(9, -1)

(1, -9)

(0, 4)

3. 4x + 2y = 34

10x – 4y = -5

(14, -2)

(3.5, 10)

(18, 0)

4. 11x – 13y = 89

-11x + 13y = 107

(0, 0)

(11, -13)

(-11, 13)

no solution

5. 3x + 6y = 42

-7x + 8y = -109

(-4, 14)

(-10, 2)

(0, 7)

(15, )

6. You have a total of 21 coins, all nickels and dimes. The total value is $1.70. Write and solve a system of equations to find the number of dimes d and the number of nickels n that you have.

n + d = 21, n + d = 1.70; 8 nickels, 13 dimes

n + d = 21, n – d = 1.70; 12 nickels, 9 dimes

nd + 1.70 = 21, 10n + 5d = 21; 12 nickels, 9 dimes

n + d = 21, 0.05n + 0.10d = 1.70; 8 nickels, 13 dimes

7. Business Suppose you start an ice cream business. You buy a freezer for $200. It costs you $.35 to make each single-scoop ice cream cone. You sell each cone for $1.20. Write and solve a system of equations to find the break-even point for your business.

200.35x = y, 1.20x = y; about 236 ice cream cones

0.35x = 200, 1.20x = y; about 686 ice cream cones

y = 200 + 0.35x, y = 1.20x; about 236 ice cream cones

200x = 0.35y, y = 1.20x; about 686 ice cream cones

8. To go to a campsite 12 miles away, you paddle a canoe aganist the current of a river for 4 hours. During your return trip you paddle with the current, and you travel the same distance in 3 hours. Write and solve a system of equations to find your paddling speed in still water. Find the speed of the current of the river.

x + y = 12, x – y = 7; 9.5 mi/h, 0.5 mi/h

x + y = 4, x – y = 3; 3.5 mi/h, 0.5 mi/h

x + y = 3, x – y = 4; 3.5 mi/h, 0.5 mi/h

3x + 4y = 12; 4 mi/h, 3 mi/h

y – 4 = -(x – 3)

y + 4 = -(x – 3)

y – 4 = (x – 3)

y – 4 = -(x + 3)

2. (0, -3); m = 18

y – 3 = 18x

y – 3 = -18x

y + 3 = 18x

y + 3 = -18x

3. (-7, -5); m = 0

y + 5 = x + 7

y – 5 = 0

x = -7

y = -5

4. Write an equation for the line through the points (2, -6) and (-1, -4).

y – 6 = -(x – 2)

y + 6 = (x – 2)

y + 6 = -(x – 2)

y + 6 = -(x + 2)

Write an equation of the line that is parallel to the given line and that passes through the given point.

5. x + y = 3; (5, 4)

y – 4 = (x – 5)

y – 4 = -(x – 5)

y + 4 = -(x – 5)

y – 4 = -(x + 5)

6. 3x + 2y = 1; (-2, 6)

y + 6 = -(x + 2)

y – 6 = -(x – 2)

y – 6 = -(x + 2)

y – 6 = -(x + 2)

Write an equation of a line that is perpendicular to the given line and that passes through the given point.

7. y = -4x + 2; (0,2)

y – 2 = x

y – 2 = -x

y – 2 = 4x

y + 2 = x

8. y = x + 6; (-6, 2)

y – 2 = (x + 6)

y – 2 = -(x + 6)

y – 2 = -(x + 6)

y + 6 = -(x – 2)

For Exercises 1-5, solve each system using elimination.

1. 2x + 5y= 2

3x – 5y = 53

(11, 4)

(11, -4)

(5, 0)

(5, -10)

2. -8x – 3y = 69

8x + 7y = -65

(-9, 1)

(9, -1)

(1, -9)

(0, 4)

3. 4x + 2y = 34

10x – 4y = -5

(14, -2)

(3.5, 10)

(18, 0)

4. 11x – 13y = 89

-11x + 13y = 107

(0, 0)

(11, -13)

(-11, 13)

no solution

5. 3x + 6y = 42

-7x + 8y = -109

(-4, 14)

(-10, 2)

(0, 7)

(15, )

6. You have a total of 21 coins, all nickels and dimes. The total value is $1.70. Write and solve a system of equations to find the number of dimes d and the number of nickels n that you have.

n + d = 21, n + d = 1.70; 8 nickels, 13 dimes

n + d = 21, n – d = 1.70; 12 nickels, 9 dimes

nd + 1.70 = 21, 10n + 5d = 21; 12 nickels, 9 dimes

n + d = 21, 0.05n + 0.10d = 1.70; 8 nickels, 13 dimes

7. Business Suppose you start an ice cream business. You buy a freezer for $200. It costs you $.35 to make each single-scoop ice cream cone. You sell each cone for $1.20. Write and solve a system of equations to find the break-even point for your business.

200.35x = y, 1.20x = y; about 236 ice cream cones

0.35x = 200, 1.20x = y; about 686 ice cream cones

y = 200 + 0.35x, y = 1.20x; about 236 ice cream cones

200x = 0.35y, y = 1.20x; about 686 ice cream cones

8. To go to a campsite 12 miles away, you paddle a canoe aganist the current of a river for 4 hours. During your return trip you paddle with the current, and you travel the same distance in 3 hours. Write and solve a system of equations to find your paddling speed in still water. Find the speed of the current of the river.

x + y = 12, x – y = 7; 9.5 mi/h, 0.5 mi/h

x + y = 4, x – y = 3; 3.5 mi/h, 0.5 mi/h

x + y = 3, x – y = 4; 3.5 mi/h, 0.5 mi/h

3x + 4y = 12; 4 mi/h, 3 mi/h

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