# Been working on this problem for 3 hours -- help

#### swampy

##### New member
(7/4x - 1/12)(2/3x - 12/11) = 0
cannot seem to come up with fractions that will cancel each other out. Have always had problem understanding how to multiply fractions
(21/12x - 1/12) = 0
(22/33x - 36/33) = 0
how do I figure out the x

we are learning to solve equactions by factoring using the Principle of zero products .... but my instructor never did any fractions for an example. All I understand is the there are two different values for X ---

#### Subhotosh Khan

##### Super Moderator
Staff member
swampy said:
(7/4x - 1/12)(2/3x - 12/11) = 0
What is it that you need to do? - solve for 'x'? simplify? what?

#### Subhotosh Khan

##### Super Moderator
Staff member
swampy said:
(7/4x - 1/12)(2/3x - 12/11) = 0
cannot seem to come up with fractions that will cancel each other out. Have always had problem understanding how to multiply fractions
(21/12x - 1/12) = 0 <<<< You did this correctly

$$\displaystyle \frac{21}{12}x \, = \, \frac{1}{12}$$

$$\displaystyle x \, = \, \frac{1}{12}\cdot \frac{12}{21}$$

$$\displaystyle x \, = \, \frac{1}{21}$$

similarly solve the next equation

(22/33x - 36/33) = 0
how do I figure out the x

#### mmm4444bot

##### Super Moderator
Staff member
swampy said:
(21/12x - 1/12) = 0

(22/33x - 36/33) = 0

how do I figure out the x

It is more clear to put the grouping symbols around the fractional coefficient.

(21/12)x - 1/12 = 0

(22/33)x - 36/33 = 0

Solve each for x by first moving the constant to the right-hand side, followed by multiplying both sides by the reciprocal of the coefficient on x.

#### Denis

##### Senior Member
swampy said:
(21/12x - 1/12) = 0
(22/33x - 36/33) = 0
Another way:
(21/12x - 1/12) = 0
Clearer if you write it this way:
21x / 12 - 1/12 = 0
(21x - 1) / 12 = 0
21x - 1 = 0
Finish it.
Do the other one similarly.