Question

How do you solve $ 9x - 7 = - 7 $ ?

Answer 1

Hint: A linear equation is an equation for a straight line. The term which is involved in a linear equation is either a constant or a single variable or product of a constant. The two variables can never be multiplied. All linear equations have a line graph. Linear equations are the same as linear functions. The general form of writing a linear equation is $ y = mx + c $ and $ m $ is not equal to zero, where $ m $ is the slope and $ c $ is the point on which it cuts the y-axis. $ y = mx + c $ is also known as the equation of the line in slope-intercept form. This given question is a linear equation and can be rewritten as $ 9x + \left( { - 7} \right) = - 7 $ , here, $ m $ is 9 and $ c $ is -7.

Complete step-by-step answer:
Given linear equation $ 9x - 7 = - 7 $ ,
In order to simplify and get the value of x, we are first required to add $ 7 $ to both the left and right-hand side.
 $ 9x - 7 + 7 = - 7 + 7 $
Now by simple addition, we get;
 $ 9x = 0 $
To further solve the equation, we need to divide left-hand and right-hand side by $ 9 $ .
 $ \dfrac{{9x}}{9} = \dfrac{0}{9} $
Now after cancelling the same terms in numerator and denominator we get;
 $
 \Rightarrow x = \dfrac{0}{9} \\
  x = 0 \\
  $ $ $
Hence, the value of $ x $ is $ 0 $ .
So, the correct answer is “0”.

Note: Now that we know the value of $ x $ is $ 0 $ , there is a way to double check our answer. In order to double check the solution we are supposed to substitute the value of $ x $ which we got as $ 0 $ in the given equation, $ 9x - 7 = - 7 $
 $
   \Rightarrow 9x - 7 = - 7 \\
   \Rightarrow 9(0) - 7 = - 7 \\
   \Rightarrow 0 - 7 = - 7 \\
   \Rightarrow - 7 = - 7 \;
  $
Now, the left-hand side is equal to the right-hand side. So, we can conclude that our solution or the value of $ x $ which we calculated was correct.