(Closed) Math help – anyone? Quick quick!

posted 5 years ago in The Lounge
Post # 4
Member
1581 posts
Bumble bee
  • Wedding: June 2011

a is correct

Post # 5
Member
524 posts
Busy bee
  • Wedding: March 2013 - Callanwolde Fine Arts Center

First you need to determine what the values of x and y are.

x+6y=22 therefore x=22-6y

Plug that back into the first equation: 5(22-6y)+4y=32

Solve for y:
110-30y+4y=32
110-26y=32
78=26y
3=y (daisys)

Use y to solve for x: x=4. (roses)

Check your work using the other equation. The answer is then A

 

Post # 7
Member
527 posts
Busy bee

You wanted to know the process.  Here it is:

You have two equations:

5x+4y=32

x+6y=22

 

We now know that x=22-6y.

Substitute that in with your first equation:

5(22-6y)+4y=32

110-30y+4y=32

110-26y=32

110-110-26y=32-110

-26y=-78

y=3

 

 

Post # 10
Member
527 posts
Busy bee

@peachacid:  OK, I’m not 100% on this one.  I googled the math problem to find the diagram, since I think this is actually really important.

 

 

We know the slope is 2/3.  That means on a graph, it will be 2 up and 3 over.  If the height of 2 points is 6 feet, then the length between each point must be 3 feet.  So if the length the ball rolled is three points, the length must be 9 feet.

 

Sorry – I wasn’t great at graphing and using slope to solve problems!!  I’m fairly sure that this is the right answer, but I’m sure there is a better way to find it!!

 

Post # 11
Member
2712 posts
Sugar bee
  • Wedding: September 2012

@peachacid:  For the rolling ball problem, you’re going to want to use the equation for a line:

y = mx + b  where m is the slope of the line (2/3) and b is where the line intersects the y-axis.

We will assume that b = 0 since it really doesn’t matter where exactly the line intersects the y-axis.  We are looking for a delta/change and not specific coordinates.  Does that make sense?

So now you have a lovely equation of:

y = (2/3)*x

You know y at 2 points (10 and 4) and now you just need to find the x location for those 2 points (x1 and x2).

10 = (2/3) * x1      and       4 = (2/3) * x2

x1 = 15                             x2 = 6

 

To figure out how far the ball has rolled horizontally along the x, you just find the difference between x1 and x2.

x1 – x2 = 9.  So the answer is b. 

 

You don’t need to draw the graph, but it might also be beneficial to draw it out as mrshunnybunches did just to get a visual.  However, you don’t want to rely on plotting alone.  It works nicely in this problem, but it won’t always.

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