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solve the simultaneous equation y=3x+5, y=4x^2+x

3x + 5 = 4x² + x
4x²-2x-5=0
x=1.4, -0.9
when x=1.4 y=3(1.4)+5=9.2
when x=-0.9 y=3(0.9)+5=7.7
x = 1.4, y = 9.2
x = -0.9, y = 7.7
i got it wrong :frown:

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Reply 1
Original post by iizhaque
3x + 5 = 4x² + x
4x²-2x-5=0
x=1.4, -0.9
when x=1.4 y=3(1.4)+5=9.2
when x=-0.9 y=3(0.9)+5=7.7
x = 1.4, y = 9.2
x = -0.9, y = 7.7
i got it wrong :frown:


You've not posed the question or how you know you got it wrong, but
3*(-0.9) + 5 is not 7.7
I got:
x=1.4,y=9.2
x=-0.9,y=2.3
You just made a small mistake by accidently doing 3(0.9) instead of 3(-0.9)
Reply 4
its still wrong for some reason
Original post by iizhaque
its still wrong for some reason

What's the actual answer?
Reply 6
Original post by iizhaque
3x + 5 = 4x² + x
4x²-2x-5=0
x=1.4, -0.9
when x=1.4 y=3(1.4)+5=9.2
when x=-0.9 y=3(0.9)+5=7.7
x = 1.4, y = 9.2
x = -0.9, y = 7.7
i got it wrong :frown:

I got the same answer as you :/
What's the actual answer?
Reply 7
Attachment not found

3x+5=4x²+x
4x²-2x-5=0
x=1.4, -0.9
y=3(1.4)+5=9.2
y=3(-0.9)+5=2.3
x = 1.4, y = 9.2
x = -0.9, y = 2.3

and its still wrong
(edited 4 years ago)
Can't see the attachment
Reply 9
Original post by chibichibi_xx
Can't see the attachment

Screenshot 2020-04-04 at 12.48.41.png
Original post by iizhaque
Screenshot 2020-04-04 at 12.48.41.png

The answers given there are just an example of how you should write them, they're not the actual answers. Used Wolfram Alpha and got x=-0.9,y=2.3 , x=1.4,y=9.2
(edited 4 years ago)
Reply 11
Original post by chibichibi_xx
The answers given there are just an example of how you should write them, they're not the actual answers. Used Wolfram Alpha and got x=-0.9,y=2.3 , x=1.4,y=9.2

i did not use the examples
Original post by iizhaque
i did not use the examples

Maybe it's just the way you've inputted the answers as they are right - maybe you're not supposed to show working and just write the answers? I have no idea how it's still wrong.
Original post by chibichibi_xx
Maybe it's just the way you've inputted the answers as they are right - maybe you're not supposed to show working and just write the answers? I have no idea how it's still wrong.

yeah that would be my suggestion, it may just want the answers
Reply 14
Original post by laurawatt
yeah that would be my suggestion, it may just want the answers

ive tried it before its probably just the website
If you do not do any rounding to 2dp until the end, the y values are 9.19 and 2,31. Does that work?
Reply 16
Original post by Matureb
If you do not do any rounding to 2dp until the end, the y values are 9.19 and 2,31. Does that work?

^^^^ Yeah, the question said to round to 2dp (for both x and y), and you've only entered answers to 1dp - try these answers.
Reply 17
is says to 2 decimal places all of yours are to 1
(edited 4 years ago)
It should be to 2 decimal placesThe answer is: x=1.40, y=9.19x= -0.90, y= 2.31(got me 5/5)
x=1.40,y=9.19x=-0.90,y=2.31

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