im back

[boogie]

a vending machine takes nickels and dimes. 5 times as many d than n total =4.40
how many each?

5n+10(n+5)=440
5n+10n+50=440
15n+50=440
15n=390
26n

boy that was awful
the 5times part is getting me

10(n+5) something wrong , dont know what


the book says 40d & 8n

trying to rework the equation

ok how about 50n+5n=55n=440
440/55=8
8*5=40 or $4.00
hhmmmm ok

the n is wrong , its 40d*.10=$4.00
n=8*.05=40cents

40 dimes and 8 nickels

if the formula looks ok here , i think im ready to move on to
set, intersections, and unions DAN

 

[boogie]

im not sure

is that formula right? im over thinking it

 

[HallsofIvy]

No. "5 times as many dimes as nickels" (not "more than" but "times as many as") means d= 5n not n+ 5. "Total 4.40" means 5n+ 10d= 440 (pennies). With d= 5n, that becomes 5n+ 50n= 55n= 440.

trying to rework the equation

ok how about 50n+5n=55n=440
440/55=8
8*5=40 or $4.00
hhmmmm ok

Yes, that is correct. (Well, almost. 8*5= 40 which is 40 cents, or $.40, not $4.00.) So you are saying you have 8 nickel and 5*8= 40 dimes. Was that what you meant by "8*5= 40 or $4.00" You should say what you were calculating. If nothing else, it will shock your teacher!

40 dimes is $4.00, 8 nickels is $.40, and those add to $4.40. Well done (more or less!).

 

[wjm11]

a vending machine takes nickels and dimes. 5 times as many d than n total =4.40
how many each?

5n+10(n+5)=440
5n+10n+50=440
15n+50=440
15n=390
26n

boy that was awful
the 5times part is getting me

10(n+5) something wrong , dont know what


the book says 40d & 8n

trying to rework the equation

ok how about 50n+5n=55n=440
440/55=8
8*5=40 or $4.00
hhmmmm ok

the n is wrong , its 40d*.10=$4.00
n=8*.05=40cents

40 dimes and 8 nickels

if the formula looks ok here , i think im ready to move on to
set, intersections, and unions DAN

You need to start by clearly defining your variables. If you do not do that, it is easy to become confused as to what they really stand for.

Let d = NUMBER of dimes (NOT an amount of money)
Let n = NUMBER of nickels (NOT an amount of money)

1st Statement: There are five times as many dimes as nickels.
1st Equation: d = 5n
Example: If the number of nickels were 7, the number of dimes would be 35.

2nd statement: the combined value of the nickels and dimes is $4.40
We must multiply the number of dimes times the value of one dime (.10) and the number of nickels times the value of one nickel (.05).
2nd Equation: (.10)d + (.05)n = $4.40

Next, substitute the 1st equation into the 2nd equation and solve.

 

[boogie]

thanks, now something a little different . graph inequalities

2x-3y<6
i can find test points.
the question i have is
how do know which way
the line is going?
i can figure out x+y=6 is the #1 quadrant
with left slope\

Is it just a matter of finding a slope
per previous chapters.

punching in 10 test points, seems to be
sorta less efficient


DAN

also doing two variables

 

[Bob Brown MSEE]

Hi Boogie

I am new to FMH too.
2x-3y=6 has right slope /

What is the quetion part of the problem that you were assigned?

 

[wjm11]

2x-3y<6
i can find test points.
the question i have is
how do know which way
the line is going?
i can figure out x+y=6 is the #1 quadrant
with left slope\

Is it just a matter of finding a slope
per previous chapters.

punching in 10 test points, seems to be
sorta less efficient


DAN

also doing two variables

Please post new problems in a new thread.

To plot lines and inequalities, I recommend you learn about "slope-intercept" form first: http://www.purplemath.com/modules/strtlneq.htm

That will make things much easier and quicker than making a table with ten points and then plotting the points.

For examples and explanations on inequalities, visit here: http://www.purplemath.com/modules/syslneq.htm

 

[HallsofIvy]

If 2x+ 3y= 6, then taking x= 0 gives 3y= 6 so that y= 2. That is, one point is (0, 2). Taking y= 0 gives 2x= 6 so x= 3. That is, another point is (3, 0). The graph of 2x+ 3y= 6 is the line through those two points. Since (0, 0) gives 2(0)+ 3(0)= 0< 6, The set of points such that 2x+ 3y< 6 is the side of line 2x+3y= 6 that contains (0, 0).