An equation of the shape: * ax +
b * = 0,* *where * a* and *b* – the known numbers,* x* – an unknown
value, is called a *linear equation in one unknown. * To solve this
equation means to find the numerical value of *x * ,
at which this equation becomes an identity.

If * a * is not equal to zero ( * a* ≠ 0
), then a solution ( root ) has the shape:

*
*

If * a* = 0 , then
the* * two
cases are possible:

* *

1*.* *b * = 0,* * then 0 · *x* + 0 = 0* . * Here * x* can be *any
number* ( check this ! ).

2*.* *b * ≠ 0,* *then 0 · *x* + *b* = 0* . **There is no solution* ( check this also ).

expressions: * x*^{2}* + *2*x = x*^{2}* – *2*x
+ x – *2* *.* *Transfer all terms to the

left-hand
side of the equation. After reducing all similar terms we’ll

receive:
3*x *+ 2 = 0,* *hence *x = – *2 / 3* *.