<PRE><B>Question 615833</B>


Please note that I have used * to represent a multiply sign.

As the length of the rectangle is twice the width then you need to multiply the width of the rectangle by 2.

As follows:

2 * (3x - 1) = 2(3x - 1)

you multiply each part of the formula by two as follows:

(2*3x - 2*1) = (6x - 2)

So the length is (6x - 2)

To find an area of a rectangle you then need to multiply the width by the length:

Area = (3x - 1)*(6x - 2) or more correctly written:

(3x - 1)(6x - 2)

To solve this you have to multiply each number in the first bracket by each number in the second unit so:

i.e. let us say we have (a + b)(c + d):

we have to do the following:

a*c a*d then b*c and b*d

So for our formula:

(3x - 1)(6x - 2) = 3x*6x + 3x*-2 + -1*6x + -1*-2
                 = {{{18x^2 + -6x + -6x + 2}}}

as + - together makes a - :

                 = {{{18x^2 - 6x - 6x + 2}}}

                 = {{{18x^2 - 12x + 2}}} 

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