Math Problmes,,,,, ALg2 level... DesPearate?
ok i cant seem to solve this problem...
there are 2 equations
3y = 2x - 6
y = 1 - cx
the problem says: C is a constant, and there is no ordered pair for (x,y). find the value of the C.
( i dont quiet get that "there is no ordered pari for x,y" but i assume that they are telling that, there is no working answer for x,y ???? i have no idea)
and the choices are
a. -3/2
b. -2/3
c. 0
d. 2/3
e. 3/2
(slahses are fractions.. just making sure...)
plz help me
Comments
Hi,
The answer is b, -2/3.
The reason is that in order for there to be no ordered pair (x,y), the lines must be parallel to each other, which happens when they have the same slope. If you solve the first equation for y, it becomes y = 2/3x - 2, so its slope is 2/3. The other line must also have a slope of 2/3. Since the second equation is y = -cx + 1 in slope-intercept form, its slope is "-c".
If -c = 2/3, then just c = -2/3. That is answer b.
I hope that helps!! :-)
I assume that the problem is to find c such that there is no pair (x,y) that solves the equation.
To do this substitue the second equation on the first, getting:
3(1-cx)=2x-6
3-3cx=2x-6
9=(2+3c)x
therefore if c=-2/3 you will have
9=(2+3*(-2/3))x=(2-2)x=0 which is a contradictioin and therefore there would not exist a solution to the system.
Answer: b
c=1. x=3. y=-2.
I'll be honest--I have no idea either! This sounds like trying to solve a pair of simultaneous equations, except that for each of the possible answers, you could then solve for x and y. Are you sure you have the problem correctly stated?
[edit] Aha! Just read the answer above me--now I understand the problem, and the answer that was given is correct.
Yep, that's true. It surely means that the equations have no solution. So, work it out like this:
a1 / a2 = b1 / b2 (not)= c1 / c2
i.e. 2 / -c = 3 / 1 (not)= -6 / 1
or, 2 / -c = 3
c = -2 / 3
I guess you have been instructed this thousands of cases - do what you savour. in case you savour maths, do maths. in case you savour ICT, do ICT. Maths is a properly respected a point while in comparison with ICT. Alot of Universities seek for Maths while utilising to check a organisation appropriate degree, yet ICT does no longer knock you out of the interest. best of luck.
my answer is 9-2x/3x, pls make sure this is objective