Math Help

Archive for October, 2009

Question: boring SAT math question no.2:graphing simultaneous equations.?

HI Im trying to figure out graphing simultaneous equations for my SAT from my prep book.

I have some questions. In one of the the questions in my book it gives: solve graphically the equations 4x – y = 5 and 2x+4y=16.
for 4x – y = 5 it gives y= 4x-5 I think i’ve realised you switch the constant and variables across to get -y= -4x +5 and that you take the -y as -1 and then divide -1(-y) into -4x to get +4x and then -5 divided by -1(-y) gives you +5
but can someone tell me if this is right or how much its correct.
then for the 2nd equation
(remember these are SIMULTANEOUS GRAPHICAL OR GRAPH equations) 2x + 4y = 16 it gives y = -1/2x +4. Is that bcoz first u get 4y= -2x + 16 and then you divde 4 (4y) into itself to get y and then 4 (4y) into -2x to get -1/2 x and 4(4y) into 16 to get 4?

it says the solution for x and y are 2 and 3 which is the unique solution for both – and I get that… I’ll ask more in the next post but 4now can someone please help, with this part.

Answer: No mistakes. Well done!

A14.9 Graphing Linear Equations

Question: Does anyone know the name of a VHS tape that simplifies learning general math?

I use to have a VHS tape of learn math the simple way. This tape does not show the ways we were taught in school but much much simplier. I have a grand daughter that is in need of help with her math skills and would give anything to have that old tape!

Answer: No, I don’t.

Math Skills & Equations : How to Improve Your GMAT Math Score

What is time series?

Time series is a series of observations taken sequentially over time. Time series can be equally spaced.

What are time series used for?

The applications of time series are:

1. forecasting to give a view of an uncertain future
2. analysis to give description of what happened.

Applications and uses of time series

Forecasting

To use time series in forecasting, first construct a suitable model taking into account:

• the analysis of historical development of the series
• utilization of relevant information likely to affect future development.

When the quantity being forecast is known, incorporate the new information into the model.

Time series procedure

The procedure of time series analysis is to produce future forecast. There are two main steps to time series analysis for forecasting. The first is to forecast observation and the second is the analysis of data. Then the process is repeated incorporating new data.

Basic models of time series analysis

There are three basic models of time series analysis:

1. models for simple time trends using linear regression
2. systematic cyclical variation model of time series
3. influential or causal variable (regressions)