(maths) am i doing this right so far?

No substituting K will not be the correct approach. Try and substitute y = kx/2 + 1 into the first equation.
You will then end up with a quadratic in the first equation.
The question then specifies that they intersect once so can you now see what to do next?

(edited 5 years ago)

Reply 2

username3934898

OP

so i make them equal to each other and then solve...? @Rohan77642

Original post by rainclouds-

so i make them equal to each other and then solve...? @Rohan77642

yes make them equal to eachother, make 1 side = 0, solve for K.
for B - since you already have what K is, you can substitute it into the equations

Reply 4

3pointonefour

Original post by Rohan77642

No substituting K will not be the correct approach. Try and substitute y = -kx/2 - 1 into the first equation.
You will then end up with a quadratic in the first equation.
The question then specifies that they intersect once so can you now see what to do next?

Isn't it y = kx/2 + 1?

Reply 5

Original post by rainclouds-

so i make them equal to each other and then solve...? @Rohan77642

Not exactly solve. You now have a quadratic in x. You know that there is only 1 intersection point, therefore that means that there is only one value of x. This means what about a quadratic?

Spoiler

(edited 5 years ago)

Reply 6

Original post by 3pointonefour

Isn't it y = kx/2 + 1?

Yes sorry. Corrected. :smile:

Reply 7

Original post by rainclouds-

so i make them equal to each other and then solve...? @Rohan77642

Sorry, I made a mistake, the substitution should be y = kx/2 + 1

Reply 8

MathsLove

17

Original post by rainclouds-

am i doing this right? it just looks wrong?
please walk me through what to do from here
i know the picture looks bad but yh lol

i'm just confused i thought it's rearrange then substitute but idk

Basics, pal. There is nothing a ‘mathematical’ about this question. You just make the two equations equal.

Reply 9

username4036292

Umm...

Make y (of the bottom equation) the subject, and you get, y= 1+kx/2.
Then substitute this y in the first equation and work through it.

Original post by rainclouds-

am i doing this right? it just looks wrong?
please walk me through what to do from here
i know the picture looks bad but yh lol

i'm just confused i thought it's rearrange then substitute but idk

Reply 10

username3934898

OP

lmaoooo its ok i got it i got the answer

tysm guys free reps 4 all

Reply 11

MathsLove

17

Original post by rainclouds-

lmaoooo its ok i got it i got the answer

tysm guys free reps 4 all

You are wrong- none of the replies including mine was on the right path.

The rational as follows

Step 1: You make the two equations equal

Step 2: simplify and organise so you can clearly see what A, B and C are

Step 3: think , in order for a quadratic equation to have only one root (meaning only one solution) the DISCRIMINANT must be 0
Therefore workout the K values that makes the discriminant 0

Reply 12

username3934898

OP