brackets within brackets

**wolfhound** · October 4th 2009, 05:51 AM

hi how would I work out the following?
(3(2^2 -2)^2 -10)^2

which brackets do I calculate first please?

**e^(i*pi)** · October 4th 2009, 06:15 AM

Originally Posted by wolfhound

hi how would I work out the following?
(3(2^2 -2)^2 -10)^2

which brackets do I calculate first please?

Start with the innermost and move outwards:

$2^2-2 = {\color{red}2}$
${\color{red}2}^2 = {\color{blue}4}$
$3 \times {\color{blue}4} = {\color{green}12}$
${\color{green}12} - 10 = 2$
$2^2 = 4$

**wolfhound** · October 4th 2009, 06:48 AM

Thanks

**e^(i*pi)** · October 4th 2009, 07:03 AM

You can also use google calculator to check your answer. Paste the problem into google and hit search

http://www.google.com/#hl=en&source=hp&q=%283%282^2+-2%29^2+-10%29^2&aq=f&aqi=&oq=&fp=e705e53e3f505592

**wolfhound** · October 4th 2009, 07:24 AM

find value of x if x-2 =5x + 14
more helps please

I havent learned how to do these yet I just want to find out how and then I will catch on
Thanks

**mathaddict** · October 4th 2009, 07:25 AM

Originally Posted by wolfhound

find value of x if x-2 =5x + 14
more helps please

I havent learned how to do these yet I just want to find out how and then I will catch on
Thanks

HI

$x-2=5x+14$

$x-5x=14+2$

$ -4x=16 $

$ x=-4 $

**wolfhound** · October 4th 2009, 07:45 AM

Originally Posted by mathaddict

HI

$x-2=5x+14$

$x-5x=14+2$

$ -4x=16 $

$ x=-4 $

cool thanks

**wolfhound** · October 4th 2009, 07:51 AM

How about this one
find value of x if
2x-1/x+2 = 3

and
is 5 a solution of x^2 + 3x-9=(x-4)(x+21)??
If so please explain how I do it
Thanks!!!!!

**wolfhound** · October 4th 2009, 07:53 AM

actually is x =7 the first one...

**mathaddict** · October 4th 2009, 08:10 AM

Originally Posted by wolfhound

How about this one
find value of x if
2x-1/x+2 = 3

and
is 5 a solution of x^2 + 3x-9=(x-4)(x+21)??
If so please explain how I do it
Thanks!!!!!

HI again .

If you need any more help , its better to start a new thread . Well , i am going to answer this . If you have any more q's , start a new onw

$\frac{2x-1}{x+2}=3$

$2x-1=3(x+2)$

$2x-1=3x+6$

$x=-7$

$ x^2+3x-9=(x-4)(x+21) $

$x^2+3x-9=x^2+17x-84$

$3x-9=17x-84$

$14x=75$

$x=75/14$

So 5 is not a solution .

**wolfhound** · October 4th 2009, 08:14 AM

Originally Posted by mathaddict

HI again .

If you need any more help , its better to start a new thread . Well , i am going to answer this . If you have any more q's , start a new onw

$\frac{2x-1}{x+2}=3$

$2x-1=3(x+2)$

$2x-1=3x+6$

$x=-7$

$ x^2+3x-9=(x-4)(x+21) $

$x^2+3x-9=x^2+17x-84$

$3x-9=17x-84$

$14x=75$

$x=75/14$

So 5 is not a solution .

Thanks so much for your help I will start a new thread when I have more questions...

**e^(i*pi)** · October 4th 2009, 08:18 AM

You seem to have the wrong sign for both of them

$\frac{2(7)-1}{7+2} = \frac{13}{9} \neq 3$

by inspection $x = -7$

-----------------

For the 2nd one $31 \neq 26$ so 5 is not a solution

$x^2+3x-9 = x^2+17x-84$

$-14x = - 75$

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