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NavyBitz
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Not sure how’s to substitute x value into 5X²-6X-8


X=0.6 could you go step by step please
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mqb2766
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You've asked a few similar questions over the past few weeks. Why not watch
https://www.youtube.com/watch?v=puNCL73k1Bc
and ask questions about what you don't understand in that video or your expression.

I just googled
evaluate quadratic expression
so if you don't like that video, just google those terms and pick one you do?

(Original post by NavyBitz)
Not sure how’s to substitute x value into 5X²-6X-8


X=0.6 could you go step by step please
Last edited by mqb2766; 2 days ago
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MyMaths&chill
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You just replace “x” in the equation with the value you’ve been given
So write “0.6” instead of “x”, and then put it in a calculator
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kurro
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As x=0.6
substitute 0.6 into 5X²-6X-8 ---> 5(0.6)² - 6(0.6) -8

Put that in a calculator, or use bidmas. Square the 0.6 first, then multiply and finally take away.
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dextrous63
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Assuming you're using a calculator, you could just use the table function to enter the function and set from 0.6 to 0.7 step 0.1
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MyMaths&chill
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Why would you do this? It’s unnecessarily complicated and requires the same mathematical knowledge.
It won’t give you the wrong answer, but do this in an exam and you’ll probably lose a mark.

(Original post by dextrous63)
Assuming you're using a calculator, you could just use the table function to enter the function and set from 0.6 to 0.7 step 0.1
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dextrous63
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(Original post by MyMaths&chill)
Why would you do this? It’s unnecessarily complicated and requires the same mathematical knowledge.
It won’t give you the wrong answer, but do this in an exam and you’ll probably lose a mark.
You wouldn't lose a mark on a calculator paper, since the question will assume that you'll be using a calculator efficiently!
Plus it's a useful skill to practise in the event of being asked to complete a table for the purposes of drawing curves.
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