Question 77
<font size = 3>I am in year 7 and I have a question. Could you please explain the term 
Linear Equation. I have looked on the internet, but the explanations are 
too complicated, could you please explain it to me so it can make more 
sense. Thank You, Ryan aged 12
`
The first 4 letters of the word "LINEar" spell "LINE".  So an equation in 
y and x which has a graph which is a straight line, and not a curve, is 
called a "linear equation". It turns out that a linear equation is one 
that when it is simplified, has no x² or x³ or higher powers of x than 
the first power, no denominators containing x, no square roots containing
x, no cube roots containing x, etc.  Here are some examples of linear 
equations:
`
5x - 4y = 9
`
3y = 4x + 2
`
y = -7x - 2
`
(3/4)x + (1/3)y = 1/2 
`
Any equation that can be put in the form 
`
Ax + By = C
`
where A, B and C are numbers is a linear equation, i.e., its graph is
a straight line.
`
Edwin <font face = "wingdings" color = "red" size = 7>J</font>