Question

If we have an equation as \[20 = 6 + 2x\], then the value of \[x\] is
A.) 6
B.) 9
C.) 8
D.) 7

Answer 1

Hint: Given equation is a simple linear equation in one variable . We can solve this equation by using addition\subtraction properties to shift all numerical to one side and keeping the term containing variable coefficient on the other side. Then extract the value of the required variable.

Complete step-by-step solution:
Let us consider the given linear equation
\[20 = 6 + 2x\]
Now as per the given question we have to find the value of the variable \[x\], which is in right hand side of the equation moreover sign for the term containing variable is plus so when u shift it to left hand side we will get negative sign so first keep the number 20 in left hand side only now shift the term \[2x\] to left hand side the given equation reduced to
\[ \Rightarrow 20 - 2x = 6\]
Now, sign for the number 20 is positive shift the number 20 to right hand side so that the sign change to negative, so that above equation becomes,
\[ \Rightarrow - 2x = 6 - 20\]
Now ,simplify right hand side we get
\[ \Rightarrow - 2x = -14\]
Now ,we need the value of \[x\] but in the above equation coefficient of x is \[ - 2\] so shift the coefficient of \[x\] that is \[ - 2\] to right hand side so that above equation becomes
\[ \Rightarrow x = \dfrac{{-14}}{{ - 2}}\]
After simplification the required value of \[x\] is 7
Therefore, the required answer is option D.

Note: We can solve the given linear equation by shifting number 6 to left hand side so that equation becomes
\[ \Rightarrow 20 - 6 = 2x\]
After simplification we get
\[ \Rightarrow 14 = 2x\]
Now shift coefficient of x to other side we get
\[ \Rightarrow x = \dfrac{{14}}{2}\]
After simplification the required value of \[x\] is -7
Therefore, required answer is option D
So we get the same answer as above .