This is some homework problems i dont know how to do it is Writing Eqautions of Lines?

sfroggy5

2008-10-11 08:56:11 UTC

Linear equations are equations that form a line.

True

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Which of the following equations has a slope of ½ and a y-intercept of -2?

y = ½x - 2

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Write the equation of the line that contains the points (2, 2) and (-3, 12).

Here is part of the answer. Can you identify the missing part?

y = -2x + ___

2 = -2(2) + b

2 = -4 + b

6 = b

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MATCHING EXERCISE

Match the terms with the definitions.

Term Definition

m = -4 and contains the point (0,2) A) y = -4x + 2

m = 2 and contains the point (0,4) B) D) y = 2x + 4

m = 2, b = -4 C) y = 2x - 4

m = 0 and contains the point (0,2) y = 2

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Which equation has a slope of 2 and contains the point (4,-4)?

y = 2x - 12

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The line y = 3x + 5 crosses the y axis at ______?

Entry 1: (0, 5)

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Write the equation of a line which contains the point (2,4) and (-2,2)

y = ½x + 3

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What type of lines have a slope of zero (vertical, horizontal, perpendicular, or diagonal?)

Entry 1: horizontal

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The equation y = ¾x - 3 crosses the y axis at 3

False it crosses at (0, -3)

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Write the equation of a line with the slope of -2 which contains the point (3,6)

Show all work to receive credit for this problem.

y = -2x + b

6 = -2(3) + b

6 = -6 + b

12 = b

y = -2x + 12

cappicone

2008-10-11 09:11:50 UTC

1. TRUE since all linear lines are straight

2. ok for question 2 the answer is y = ½x - 2. This is because the formula of a linear line is y=mx + b. The y stands for the y point on the graph. The a is the slope of the line. and the b is the y-intercept.

3.The question already gives you the slope so all we need to do is find the y-intercept. In order to do this we need to sub the point values into the question. y=-2x+ (y-intercept). so i am going to use the point (2,2). So we sub them for x and y in the equation. 2 = -2(2)+ y-intercept. now all we need to do is solve so y-intercept = 2 + 4...y-intercept = 6. Therefore the final answer is y=2x+6

4. m = -4 and contains the point (0,2) :::(Answer:: y = -4x + 2)

m = 2 and contains the point (0,4) :::(Answer::y=2x+4)

m = 2, b = -4:::(Answer:: y=2x-4)

m = 0 and contains the point (0,2):::(Answer::y=2)

5.For this question we already know that the slope of the line is 2. So we can eliminate the first equation..y = 4x - 4. So now we are remaining with 3 equations. To find the right one we need to sub in the x and y value (4, -4). so we know that x = -4 and y = -4. So we sub it into each question until you get an answer -4 = -4. Therefore the third equation is the write answer since we do get the answer -4= -4.

6. To find this answer to this question we only need to sub in the value 0 into the x. This is because the y-intercept is the value when the x is 0. Therefore using the formula y = 3x+5..subbing in the value zero for x. y=5. Therefore the y-intercept is zero.

7.Answer is:::y = ½x + 3

8.horizontal.

9. False since the equation is y = ¾x - 3. And the y-intercept value is -3. Therefore the y-intercept can't be 3. It has to be -3.

10. So first we know that the slope is -2. So we can sub that value for m. y = -2x+ b. Next we have the x and y values 3, 6. So we sub that into the equation. 6 = -2(3)+b. 6= -6 +b. b=12. Now that we know we can sub in the value for m and b. y = -2x+12.

Buddingwriter92

2008-10-11 09:08:06 UTC

True.

y=(1/2)x-2.(3rd equation).

y= -2x +6

m = -4 and contains the point (0,2) A) y = -4x + 2

m = 2 and contains the point (0,4) D) y = 2x + 4

m = 2, b = -4 C) y = 2x - 4

m = 0 and contains the point (0,2) B) y = 2

y = 2x - 12

crosses y-axis at (0,5)

y = ½x + 3, passes tru' (2,4) and (-2,2)

vertical lines slope 0

False. Not 3, -3

Last Question.

m=-2.

Point is (3,6), so x1=3, y1=6

Equation of line is y-y1=m(x-x1)

=> y-6= -2(x-3)

=> y-6=6-2x

=> y=12-2x