in the xy plane line k has a positive slope and and x-intercept 4. if the area of the triangle formed by line k and the two axes is 12, what is the y intercept of line k
a. -6
b. -4
c. -3
d. 3
e. 6
please explain how you get the right anwser
xy plane
This topic has expert replies
IMO Eballer12q wrote:in the xy plane line k has a positive slope and and x-intercept 4. if the area of the triangle formed by line k and the two axes is 12, what is the y intercept of line k
a. -6
b. -4
c. -3
d. 3
e. 6
please explain how you get the right anwser
Positive slope cut x in 4 (the line is descending from up left to down right) So the base of the triangle is 4.
Then 4*Y/2=12
Answer y=6
Is a 3-4-5 triangle
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Area = 1/2(bh) = 12
.5(4)h=12
h=6
so the absolute value of the y-intercept is 6. We can't know it is positive or negative unless we know more about line k. Since we know it has a positive x-intercept and is positively sloped, its y-intercept is negative.
A
.5(4)h=12
h=6
so the absolute value of the y-intercept is 6. We can't know it is positive or negative unless we know more about line k. Since we know it has a positive x-intercept and is positively sloped, its y-intercept is negative.
A
I agree fully. Thanks for the nice explanationcm47323 wrote:Area = 1/2(bh) = 12
.5(4)h=12
h=6
so the absolute value of the y-intercept is 6. We can't know it is positive or negative unless we know more about line k. Since we know it has a positive x-intercept and is positively sloped, its y-intercept is negative.
A
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I also arrived @ the answer the same way. Well done.cm47323 wrote:Area = 1/2(bh) = 12
.5(4)h=12
h=6
so the absolute value of the y-intercept is 6. We can't know it is positive or negative unless we know more about line k. Since we know it has a positive x-intercept and is positively sloped, its y-intercept is negative.
A
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hey could someone explain the reasoning behind the highlighted part ?
cm47323 wrote:Area = 1/2(bh) = 12
.5(4)h=12
h=6
so the absolute value of the y-intercept is 6. We can't know it is positive or negative unless we know more about line k. Since we know it has a positive x-intercept and is positively sloped, its y-intercept is negative.
A
- thephoenix
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positive slope means the line is always be falling toward x axis
now base is 4;and area is 12 ;therefore ht is 6
since line is having a +ve x intercept and a +slope the line is in 4th quardant
hence ht is -6
A
now base is 4;and area is 12 ;therefore ht is 6
since line is having a +ve x intercept and a +slope the line is in 4th quardant
hence ht is -6
A
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i get that.
But doesnt a positive slope rise from the 3rd quadrant towards the first quadrant ?
and a negative slope falls in the direction of second quadrant to the fourth quadrant???
If its rising from the 3rd quadrant(being a +ve slope), the positive x intercept would be in the first quadrant....and so would the y intercept be. isnt it ?
Can someone please draw the direction of the slopes ?
But doesnt a positive slope rise from the 3rd quadrant towards the first quadrant ?
and a negative slope falls in the direction of second quadrant to the fourth quadrant???
If its rising from the 3rd quadrant(being a +ve slope), the positive x intercept would be in the first quadrant....and so would the y intercept be. isnt it ?
Can someone please draw the direction of the slopes ?
thephoenix wrote:positive slope means the line is always be falling toward x axis
now base is 4;and area is 12 ;therefore ht is 6
since line is having a +ve x intercept and a +slope the line is in 4th quardant
hence ht is -6
A
Many members have posted answer as 6.baller12q wrote:in the xy plane line k has a positive slope and and x-intercept 4. if the area of the triangle formed by line k and the two axes is 12, what is the y intercept of line k
a. -6
b. -4
c. -3
d. 3
e. 6
please explain how you get the right anwser
If the two points are (4,0) and (0,6)
then the slope of the line would be= (y1-y2)/(x1-x2)=(6-0)/(0-4)=6/-4 < 0
but slope is mentioned positive hence, -6 is correct