Question

How do you solve \[5(2x - 4) = 4\] ?

Answer 1

Hint: In the given problem we need to solve this for ‘x’. We can solve this using the transposition method. The common transposition method is to do the same thing (mathematically) to both sides of the equation, with the aim of bringing like terms together and isolating the variable (or the unknown quantity). That is we group the ‘x’ terms one side and constants on the other side of the equation.

Complete step by step solution:
Given, \[5(2x - 4) = 4\] .
Expanding the brackets we have,
 \[10x - 20 = 4\]
We transpose \[ - 20\] which is present in the left hand side of the equation to the right hand side of the equation by adding \[20\] on the right hand side of the equation.
 \[10x = 4 + 20\]
 \[10x = 24\]
We transpose \[10\] to the right hand side of the equation by dividing \[10\] on the right hand side of the equation.
 \[x = \dfrac{{24}}{{10}}\]
 \[ \Rightarrow x = \dfrac{{12}}{5}\] . This is the exact form.
 \[ \Rightarrow x = 2.4\] . This is the decimal form.
So, the correct answer is “x = 2.4”.

Note: We can check whether the obtained solution is correct or wrong. All we need to do is substituting the value of ‘x’ in the given problem.
 \[5(2(2.4) - 4) = 4\]
 \[5(4.8 - 4) = 4\]
 \[5(0.8) = 4\]
 \[ \Rightarrow 4 = 4\]
Hence the obtained answer is correct.