The line y=2x-3 meets the x-axis at the point P, and the line 3y+4x=8 meets the x-axis at the point Q. The two lines intersect at the point R.
find the coordinates of R
i really dont know how to do this
please show me how to do it
thank you
find the coordinates of R
i really dont know how to do this
please show me how to do it
thank you
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You need to solve the two equations together
One way to do this is to use the first equation in the second:
y=2x-3
3y+4x=8
so
3(2x-3) + 4x = 8
You now need to expand the brackets and do some algebra to find the x co-ordinate of R, the use the first equation to find y.
You should get x=1.7 and y=0.4
Another way would be to draw graphs for both lines.
One way to do this is to use the first equation in the second:
y=2x-3
3y+4x=8
so
3(2x-3) + 4x = 8
You now need to expand the brackets and do some algebra to find the x co-ordinate of R, the use the first equation to find y.
You should get x=1.7 and y=0.4
Another way would be to draw graphs for both lines.
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Y = 2X -3 and 3Y + 4X = 8 are two lines which intersect at point R.
Let's rewrite the two equations as Y = something
Y = 2X - 3 ..................first line equation unchanged (equation 1)
Y = ( 8 - 4X)/3 ...........subtracted 4X from both sides and divided both sides by 3 (equation 2)
If the lines intersect this means that at the point of intersection both lines are equal i.e. the point of intersection lies on both lines. This means that:
2X - 3 = (8 - 4X)/3 ......make the two lines equal
6X - 9 = 8 - 4X ...........multiply both sides of the equation above by 3
10X = 17 ............put the Xs on one side and the constants on the other
X = 17/10
We now find Y
from the equation of the first line we have:
Y = 2*17/10 - 3 = (34 -30)/10 = 4/10 = 2/5
from equation 2
Y = (8 - 4*17/10)/3 = (8 - 2*17/5)/3 = (40 - 34)/15 = 6/15 = 2/5
so the point of intersection is (17/10, 2/5)
Let's rewrite the two equations as Y = something
Y = 2X - 3 ..................first line equation unchanged (equation 1)
Y = ( 8 - 4X)/3 ...........subtracted 4X from both sides and divided both sides by 3 (equation 2)
If the lines intersect this means that at the point of intersection both lines are equal i.e. the point of intersection lies on both lines. This means that:
2X - 3 = (8 - 4X)/3 ......make the two lines equal
6X - 9 = 8 - 4X ...........multiply both sides of the equation above by 3
10X = 17 ............put the Xs on one side and the constants on the other
X = 17/10
We now find Y
from the equation of the first line we have:
Y = 2*17/10 - 3 = (34 -30)/10 = 4/10 = 2/5
from equation 2
Y = (8 - 4*17/10)/3 = (8 - 2*17/5)/3 = (40 - 34)/15 = 6/15 = 2/5
so the point of intersection is (17/10, 2/5)
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y = 2x - 3
y = (-4x+8)/3
the lines intercepts when y1=y2 and x1=x2
2x - 3 = -4/3 x + 8/3
2x + 4/3 x = 3 + 8/3
6x + 4x = 9 + 8
10x = 17
x= 17/10
x= 1.7
y= 2(1.7)-3
y= 0.4
y = (-4x+8)/3
the lines intercepts when y1=y2 and x1=x2
2x - 3 = -4/3 x + 8/3
2x + 4/3 x = 3 + 8/3
6x + 4x = 9 + 8
10x = 17
x= 17/10
x= 1.7
y= 2(1.7)-3
y= 0.4