hielly's maths thread

[Flaming_Arrow]

is that what you meant?

could you please type it in latex its easier to understand the question

[Flaming_Arrow]

[Hielly]

how did you gt to the 6 ?

since they have the same power we times the bases

okay in this case you had to times them but here you didnt times them?

if you times it, shouldn't it be..

[Flaming_Arrow]

how did you gt to the 6 ?

since they have the same power we times the bases

okay in this case you had to times them but here you didnt times them?

if you times it, shouldn't it be..

they have the same base meaning we add the powers.
 
also

[Hielly]

okay i need confirmation in this question

a contractor employed eight men and three biys for one day and paid them a total of $2240. another day he employed six men and eighteen boys for $4200. what was the daily eater he paid each man and each boy?
y= boy
x=men

for y i got160.38 which is correct
and x i got -219.86 which is correct? besides the minus sign.

the answer is 219.86 without the minus sign is my answer with the minus right or wrong?

[Flaming_Arrow]

times the first equation by 6



take away from the 2nd equation

[Hielly]

okay

solve the simultaneous equations

3x+2y=2
2x-3y=6

i found out that y=-14/13 and got x=-22/9 ??

[Flaming_Arrow]

times the first equation by 3 and the 2nd by 2





add the equations





sub in x to any equation

[Hielly]

quick one.

write and equation:

a machine working at a constant rate produces n bolts in 5 minutes. it produces 2400 bolts in 1 hours.

n=5 minutes
2400=60 minutes.. stuck on next step

[Flaming_Arrow]

is that all the info given?

[shinny]

When dealing with units that are a bit obscure, just write it out so you don't get confused and cancel units as you go.

Let x be the rate at which bolts are made
x bolts/minute = n bolts / 5 minutes . . . 1
x bolts/minute = 2400 bolts / 60 minutes . . . 2
Equate 1 and 2 to get;
n/5=2400/60
=40
n=200 bolts

The main thing you forgot is that the units on both sides of an equation need to be equal, otherwise the terms themselves can't possibly be equal (except for multiples of units such as grams and kilograms of course). If you're only given two pieces of information like in this case, make a 'dummy' term such as the x I had which is effectively just something which cancels out any units. Using your working out, this thought process might be more along the lines of;
n bolts~5 minutes
n bolts/y bolts=5 minutes/z minutes (units 'cancel out' now)
n/y=5/z
and then merge the constants y and z and transpose to become x to get
n/5=x
Of course this is purely for explanatory reasons and isn't something you'd write in an exam, but I'm just trying to show how you could come up with such a process and the reasons behind it.

[Flaming_Arrow]

where x is minutes.

[shinny]

Oh right the point was to write the equation. My bad! Just remember to define your variables (y and x) too I guess.

[Flaming_Arrow]

did u mean?

[Flaming_Arrow]

cross multiply





use quadratic formula