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

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iizhaque
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#1
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#1
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
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mqb2766
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(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
You've not posed the question or how you know you got it wrong, but
3*(-0.9) + 5 is not 7.7
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chibichibi_xx
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#3
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I got:
x=1.4,y=9.2
x=-0.9,y=2.3
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james.osborne
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#4
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You just made a small mistake by accidently doing 3(0.9) instead of 3(-0.9)
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iizhaque
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#5
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#5
its still wrong for some reason
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chibichibi_xx
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#6
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(Original post by iizhaque)
its still wrong for some reason
What's the actual answer?
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Junaki
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#7
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(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
I got the same answer as you :/
What's the actual answer?
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iizhaque
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#8
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Attachment 892214
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
Last edited by iizhaque; 1 year ago
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chibichibi_xx
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Can't see the attachment
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iizhaque
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#10
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(Original post by chibichibi_xx)
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chibichibi_xx
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(Original post by iizhaque)
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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
Last edited by chibichibi_xx; 1 year ago
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iizhaque
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#12
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(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
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chibichibi_xx
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(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.
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laurawatt
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#14
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(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
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iizhaque
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(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
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Matureb
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#16
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If you do not do any rounding to 2dp until the end, the y values are 9.19 and 2,31. Does that work?
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Junaki
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(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.
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A_C_H
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#18
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#18
is says to 2 decimal places all of yours are to 1
Last edited by A_C_H; 1 year ago
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cusas004.304
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#19
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#19
It should be to 2 decimal placesThe answer is: x=1.40, y=9.19x= -0.90, y= 2.31(got me 5/5)
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