Question

How to solve \[\dfrac{x}{{ - 4}} = 9\]?

Answer 1

Hint: In the given question, we have been given an algebraic expression. In the expression, a variable is divided with a constant. Then, the complete left-hand side, which consists of the variable and constant, is equal to another constant. We have to solve this equation. We can easily do so by using the concept of cross-multiplication.

Formula Used:
\[\dfrac{a}{b} = c \Rightarrow a = b \times c\]

Complete step by step answer:
The given expression to be simplified is:
\[\dfrac{x}{{ - 4}} = 9\]
We know, \[\dfrac{a}{b} = c \Rightarrow a = b \times c\].
Substituting \[a = x\], \[b = - 4\] and \[c = 9\], we have,

\[x = - 4 \times 9 = - 36\].

Note:
In the given question, we had to simplify the value of an expression. To do that, we just take the denominator to the other side, this method is commonly called cross-multiplication. It is a point to note that while multiplying a negative term (positive becomes negative and vice-versa) and any positive term becomes negative.