Algebra

[speedyj]

a=2, b=-4, c=-3


a³ - 2b - 4c²

Can someone solve this please?

 

[SideWinder]

(2x3) - (2x-4) - (4x-3x2).

I think...i got a C for Maths GCSE.

 

[Ahleckz]

Edited so no one knows I was *ahem* right *ahem*

 

[Fegruson]

http://www.google.co.uk/search?hl=en&safe=off&rlz=1G1GGLQ_ENUK354&q=(2^3)+-+(2+x+(-4))+-+(4+x+(-3)^2)&aq=f&aqi=&aql=&oq=&gs_rfai=

 

[SideWinder]

I wasn't going to do his homework for him...!

 

[Fegruson]

Not even sure it's correct tbh!

 

[fidget]

http://www.myalgebra.com/algebra_solver.aspx

Answer: -20

 

[Lydzor]

I got -20 also.

 

[Cosimo]

OP should look in here:

http://www.wolframalpha.com/examples/Math.html

Must be going back to school tomorrow.

 

[icysniper]

hmm i get 124

8 - -8 - -108

= 8+8+108 = 124

EDIT: my bad lemme work it out again

yeh got -20, for some reason i thought it was cubed for C, wtf was i thinking?

 

[DB_SamX]

(2x3) - (2x-4) - (4x-3x2).

I think...i got a C for Maths GCSE.

Would be an F really here.

 

[fidget]

OP should look in here:

http://www.wolframalpha.com/examples/Math.html

Cool. Someone has found a use for it at last

 

[Hamster]

-20. This is very basic year 8 maths.

 

[Lydzor]

I'm guessing people are misunderstanding powers and how to calculate minus numbers.

 

[SideWinder]

...was my method correct by the way?

 

[speedyj]

a=2, b=-4, c=-3

a³ - 2b - 4c²

As before, start with the "Not thinking" line:
2³ -8x(-4) -4x(-3)²

now sort out the numbers:
8 not 6!!!! It's 2x2x2 = 4x2 = 8
+ 32 minus times a minus is a plus
- 36 do it carefully, (-3)² = +9, -4x9 = -36
= 4

This is the explanation on a website my daughter has been pointed to by her teacher.

 

[Skillmister]

(2x2x2) - (-4x2) - (4x(-3x-3))
=
8 - -8 - (4x9)
=
16--36
=
-20




edit: its -20

 

[TheCenturion]

a=2, b=-4, c=-3


a³ - 2b - 4c²

Can someone solve this please?

Come on people this isn't hard at all!

I'll even put it into words!

2 cubed is 8

2 times -4 is -8

-3 squared is 9, and 9 x 4 is 36

8 take away negative 8 is 16. 16 take away 36 is -20

That was simples.

 

[Lightnix]

a=2, b=-4, c=-3

a³ - 2b - 4c²

As before, start with the "Not thinking" line:
2³ -8x(-4) -4x(-3)²

Where'd you get -8x(-4) from then?

 

[speedyj]

Where'd you get -8x(-4) from then?

Its not my expression, I don't understand where that comes from either, it is on the website that my daughter was pointed to.

It looks wrong to me also.