# Really Hard MathsWatch

Thread starter 4 years ago
#1
i have got some work which i dont understand how to do
i have to find x from the formula x^2+4x+4=0 i have no idea were to start i tried x^2+4x=4 then x(x+4)=4 so x=4 and x=1 but the back of the book says x=-2 is the book wrong?
0
4 years ago
#2
(Original post by user6)
i have got some work which i dont understand how to do
i have to find x from the formula x^2+4x+4=0 i have no idea were to start i tried x^2+4x=4 then x(x+4)=4 so x=4 and x=1 but the back of the book says x=-2 is the book wrong?
factorize the quadratic or use the quadratic formula.

do you remember this from your GCSE?
0
4 years ago
#3
You aren't facorising it correctly. What you should be trying to do is trying to split x^2 + 4x + 4 into 2 brackets. E.g (x * ?)(x * ?)
0
Thread starter 4 years ago
#4
(Original post by TeeEm)
factorize the quadratic or use the quadratic formula.

do you remember this from your GCSE?
i did factorize it but the answer is wrong? i dont think we done quadratic formula yet
0
Thread starter 4 years ago
#5
(Original post by AwesomeSauce#1)
Aren't facorising it correctly. What you should be trying to do is be trying to split x^2 + 4x + 4 into 2 brackets. E.g (x * ?)(x * ?)
so like (x+4x)(x+4)?
0
4 years ago
#6
(Original post by user6)
so like (x+4x)(x+4)?
Like (x+4)(x+4)

That's not the answer though 0
4 years ago
#7
(Original post by user6)
i did factorize it but the answer is wrong? i dont think we done quadratic formula yet
book is correct

factorize into 2 brackets with the right hand side = 0

(x+...)(x+...)=0

does this ring any bells?

PS what course are you doing?
0
4 years ago
#8
(Original post by user6)
i have got some work which i dont understand how to do
i have to find x from the formula x^2+4x+4=0 i have no idea were to start i tried x^2+4x=4 then x(x+4)=4 so x=4 and x=1 but the back of the book says x=-2 is the book wrong?
Your method doesn't work - try putting x = 1 or x = 4 into your original equation and you'll see why!

Have you learned how to solve quadratic equations?
0
Thread starter 4 years ago
#9
(Original post by TeeEm)
book is correct

factorize into 2 brackets with the right hand side = 0

(x+...)(x+...)=0

does this ring any bells?

PS what course are you doing?
not sure what u are doing how do I get 0 from my formula? and how do I get the 2 brackets?
0
Thread starter 4 years ago
#10
(Original post by davros)
Your method doesn't work - try putting x = 1 or x = 4 into your original equation and you'll see why!

Have you learned how to solve quadratic equations?
whats wrong with x=1? 1^2+4+4=9 whats wrong?
0
4 years ago
#11
(Original post by user6)
not sure what u are doing how do I get 0 from my formula? and how do I get the 2 brackets?
Have you been through this in class or with a teacher?

You shouldn't be trying to tackle something like this if you haven't been taught the method to begin with 0
Thread starter 4 years ago
#12
(Original post by AwesomeSauce#1)
Like (x+4)(x+4)

That's not the answer though how do i do this because (x+4)(x+4)=x^2+16 how does that help?
0
4 years ago
#13
(Original post by user6)
not sure what u are doing how do I get 0 from my formula? and how do I get the 2 brackets?
for example

if (x-2)(x+5)=0

then either
x-2=0
x=2

or
x+5=0
x=-5
0
4 years ago
#14
(Original post by user6)
whats wrong with x=1? 1^2+4+4=9 whats wrong?
What's wrong is that you're trying to get the answer 0 not 9 0
Thread starter 4 years ago
#15
(Original post by davros)
Have you been through this in class or with a teacher?

You shouldn't be trying to tackle something like this if you haven't been taught the method to begin with I have to teach myself (cannot afford a teacher lol) because i failed gcse maths and sixth form is making me resit
0
4 years ago
#16
(Original post by user6)
how do i do this because (x+4)(x+4)=x^2+16 how does that help?
That's not true either!

(x + 4)(x + 4) = x^2 + 8x + 16.

Have you covered multiplying brackets in class?
0
Thread starter 4 years ago
#17
(Original post by TeeEm)
for example

if (x-2)(x+5)=0

then either
x-2=0
x=2

or
x+5=0
x=-5
why? maths is soo hard 0
4 years ago
#18
(Original post by user6)
I have to teach myself (cannot afford a teacher lol) because i failed gcse maths and sixth form is making me resit
Nothing wrong with teaching yourself but you need to get hold a textbook or suitable revision guide that can take you through the material in an organized manner.
0
Thread starter 4 years ago
#19
(Original post by davros)
That's not true either!

(x + 4)(x + 4) = x^2 + 8x + 16.

Have you covered multiplying brackets in class?
i dont know? you can multiply brackets? i didnt know that what is ) times ) then?
0
4 years ago
#20
Use the quadratic formula.
0
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