How do you solve (3w+8)/2=25?

2 Answers
Jul 21, 2016

w = 14

Explanation:

(3w + 8)/2 = 25

3w + 8 = 50

3w = 50 - 8 = 42

Hence w = 42/3 = 14

Jul 21, 2016

w=42/3 = 14

Explanation:

color(magenta)("With practice you will be able to answer this question type in 1, 2 or 3 lines")

Gradually you manipulate the equation until you have just a single w and it is on 1 side of = and everything else on the other side.

For this equation there are three basic principles that are the ul("seed principles behind the shortcut methods")

color(brown)("Principle 1")
To maintain the 'truth' of the equation (some people use the word balance): what you do to one side of the equation you do to the other.

color(brown)("Principle 2")
To 'get rid' of an add or subtract change it to 0

color(brown)("Principle 3")
To get rid of a multiply or divide change it to 1

Note that LHS is left hand side and that RHS is right hand side.
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Given:" "color(brown)((3w+8)/2=25)

Using principle 3 to 'get rid' of the denominator of 2 on the LHS
Multiply both sides by color(blue)(2)

color(brown)((color(blue)(2))/2xx(3w+8)=color(blue)(2xx)25)color(green)(" " ->" " 3w+8=50)

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Using principle 2 to 'get rid of the 8 on the LHS

Subtract color(blue)(8) from both sides

color(brown)(3w+8color(blue)(-8)=50color(blue)(-8)color(green)(" "->" "3w=42)

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Using principle 3 to 'get rid of the 3 on the LHS

Divide both sides by color(blue)(3) to 'get rid' of the 3 on the LHS

color(brown)(3/(color(blue)(3)) w=42/(color(blue)(3))color(green)(" "->" "w=42/3)