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Factorising quadractics 'harder problems' Watch

1. I was refreshing my knowledge of GCSE Maths by factorising quadractics. I did 6 problems and then checked if my answers are right. I only got the last 5 problems right. I can't work my head around to getting the answer of the first problem (sad I know ).

The problem is: 3x^2+5x+2.

My 2 embarrassing attempts:
Spoiler:
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2. When factoring , you need to find two numbers whose sum equals and whose product equals .
In your attempts, you found the numbers , but their product does not equal .
3. It's a pain thinking of numbers to put in the brackets; I find it much easier to just complete the square or even use the quadratic formula.

You'll get

Giving you or
4. The answer to that problem is: (3x+2) (x+1)

I don't get how I got the other 5 right, when I followed the same method (used on MathsWatch, since my teacher wasn't helpful). I'll show you how I did one other problem and got it right.

5. (Original post by 34908seikj)
It's a pain thinking of numbers to put in the brackets; I find it much easier to just complete the square or even use the quadratic formula.

Giving you
And this is why simply using the formula without thought goes wrong. This is incorrect.
6. I just worked it backwards with the answer and see where I went wrong. Apparently, I should have used 2 and 3, instead of 6 and -1.

Since 6 times -1 equals -6, when multiplying the coefficient of x^2 which is 3 times the constant of 2 equals 6...

Rookie mistake by me.
7. (Original post by 34908seikj)
It's a pain thinking of numbers to put in the brackets; I find it much easier to just complete the square or even use the quadratic formula.

You'll get

Giving you or
Erm multiply those 2 expressions together and see what you get...
8. (Original post by ColossalAtom)
The answer to that problem is: (3x+2) (x+1)

I don't get how I got the other 5 right, when I followed the same method (used on MathsWatch, since my teacher wasn't helpful). I'll show you how I did one other problem and got it right.

Awesome handwriting
9. (Original post by Helg)
Awesome handwriting
I have to take high dosage of immunosuppressants, so having tremors is to be expected.
10. (Original post by ColossalAtom)
I have to take high dosage of immunosuppressants, so having tremors is to be expected.
Oh didn't know that, my cousin has the same. I personally have dyslexia which is a big obstacle for math [especially with algorithms] so I was allowed extra time in exams.
11. (Original post by ColossalAtom)
I was refreshing my knowledge of GCSE Maths by factorising quadractics. I did 6 problems and then checked if my answers are right. I only got the last 5 problems right. I can't work my head around to getting the answer of the first problem (sad I know ).

The problem is: 3x^2+5x+2.

My 2 embarrassing attempts:
I just use my calculator's quadratic solver and then turn them into the factorised form because I'm too lazy to solve them by hand :^)
12. (Original post by 34908seikj)
It's a pain thinking of numbers to put in the brackets; I find it much easier to just complete the square or even use the quadratic formula.

You'll get

Giving you or
nah.

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