How do you solve \frac { 14p } { 5} - 3= \frac { 3p } { 8} + \frac { 7} { 30}?

2 Answers
Nov 26, 2017

p=1\frac{1}{3}

Explanation:

\frac{14p}{5}-3=\frac{3p}{8}+\frac{7}{30}

Rearrange the terms so the terms with variables are on one side, and the constants are on the other side:

\frac{14p}{5}-\frac{3p}{8}=\frac{3}{70}+3

Find a common denominator on the LHS, which is 40:

\frac{14p\cdot color(red)(8)}{5\cdot color(red)(8)}-\frac{3p\cdot color(green)(5)}{8\cdot color(green)(5)}=\frac{7}{30}+3

\rightarrow\frac{122p}{40}-\frac{15p}{40}=\frac{7}{30}+3

Change the 3 on the RHS to have a denominator of 30:

\frac{112p}{40}-\frac{15p}{40}=\frac{7}{30}+\frac{90}{30}

Simplify both sides:

\frac{color(magenta)(97p)}{color(blue)(40)}=\frac{color(blue)(97)}{color(magenta)(30)}

Cross multiply:

color(magenta)(97p)\cdot color(magenta)(30)=color(blue)(40)\cdot color(blue)(97)

Evaluate both sides:

3880=2910p

Isolate for p:

p=1\frac{1}{3}

Nov 26, 2017

p=4/3

Explanation:

If an equation has fractions, you can get rid of them immediately by multiplying each term by the LCM of the denominators. (The LCD) so that you can cancel the denominators

In this case it is 120

(color(blue)(120xx) 14p)/5 - color(blue)(120xx) 3= (color(blue)(120xx)3p)/8 + (color(blue)(120xx)7)/30

(color(blue)(cancel(120)^24xx) 14p)/cancel5 - color(blue)(120)xx 3= (color(blue)(cancel(120)^15xx)3p)/cancel8 + (color(blue)(cancel(120)^4xx)7)/cancel30

336p -360 = 45p +28

336p-45p = 28+360

291p = 388

p = 388/291

p=4/3