Which of the following is equivalent??
2 answers:
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For A you would have to convert from that equation to the slope-intercept form of the equation. To do that, first add 2x to both sides, because you want to have x on the right side of the equation. And that's it! That gives you 4y = 2x + 8. And from that equation you can identify the slope (2) and the y-int (8)
For B, the same thing. Converting to slope-intercept form, just with an extra step. First, you would subtract 1y from both sides to move it to the left of the equal sign, since that's where it needs to be for slope-intercept form. That gives you -1y + 7 = -x. Don't worry about the negatives for now. Next, subtract 7 from both sides to get y by itself on the left (because that's how it is in slope-intercept form) which gives you -1y = -x - 7. Then, because you can't have negative variables, divide both sides by negative 1 (a negative divided by a negative equals a positive), to equal y = x + 7. (I've attached a picture showing my steps if the words are too confusing)
For C, you need to find the slope first, then use the slope to find the y-intercept. So subtract. (I've shown in the picture) that equals -8 over 4 which simplifies to -2. So -2 is the slope! Now to find the y-intercept, plug in an ordered pair from the problem (doesn't matter which one) and the slope to find the y-intercept (b). I'm just going to use (-2, 5). So plug in the y from the pair (5) and the slope (-2) and the x from the pair (-2) into the slope-intercept equation to equal 5 = -2(-2) + b. Since you don't know b (the y-intercept) leave it blank and solve like a one step equation! (steps in the picture). And there you have it, the slope is -2 and the y-int is 1!
For D, it's like C, but you dont have the chart. Use subtraction to find the slope. Change in y over change in x (which means subtract the y values and divide them by the difference in x values). So. You'd do 0 - 3 over -6 - 3 which equals -3 over -9, which simplifies to 1/3. And that's your slope! So to find the y-int just do the same thing you did in the last problem, plug in an ordered pair and the slope into the slope-intercept equation and solve as a one step equation (steps in picture). And there you have it, the slope which is 1/3, and the y-int which is 2.
For B, the same thing. Converting to slope-intercept form, just with an extra step. First, you would subtract 1y from both sides to move it to the left of the equal sign, since that's where it needs to be for slope-intercept form. That gives you -1y + 7 = -x. Don't worry about the negatives for now. Next, subtract 7 from both sides to get y by itself on the left (because that's how it is in slope-intercept form) which gives you -1y = -x - 7. Then, because you can't have negative variables, divide both sides by negative 1 (a negative divided by a negative equals a positive), to equal y = x + 7. (I've attached a picture showing my steps if the words are too confusing)
For C, you need to find the slope first, then use the slope to find the y-intercept. So subtract. (I've shown in the picture) that equals -8 over 4 which simplifies to -2. So -2 is the slope! Now to find the y-intercept, plug in an ordered pair from the problem (doesn't matter which one) and the slope to find the y-intercept (b). I'm just going to use (-2, 5). So plug in the y from the pair (5) and the slope (-2) and the x from the pair (-2) into the slope-intercept equation to equal 5 = -2(-2) + b. Since you don't know b (the y-intercept) leave it blank and solve like a one step equation! (steps in the picture). And there you have it, the slope is -2 and the y-int is 1!
For D, it's like C, but you dont have the chart. Use subtraction to find the slope. Change in y over change in x (which means subtract the y values and divide them by the difference in x values). So. You'd do 0 - 3 over -6 - 3 which equals -3 over -9, which simplifies to 1/3. And that's your slope! So to find the y-int just do the same thing you did in the last problem, plug in an ordered pair and the slope into the slope-intercept equation and solve as a one step equation (steps in picture). And there you have it, the slope which is 1/3, and the y-int which is 2.