Question

Solve the following equation: $21 - x = 7$

Answer 1

Hint: We have to find the value of $x$ , since the question is asked to solve the given equation. To find the value of $x$ , we are going to subtract both sides with $21$ . In subtraction which is the minus of given two or more than two numbers, but here comes the condition that in subtraction the greater number sign represented in the number will stay constant example $2 - 3 = - 1$. Hence which can be expressed in the form of $ - $ . Therefore by using the above we can solve the given equation.

Complete answer:
Since given that the equation $21 - x = 7$ and then we need to find the value of the unknown variable $x$, so we will make use of the basic mathematical operations to simplify further.
now Turing the variables on the left-hand side and also the numbers on the right-hand side we get $21 - x = 7 \Rightarrow - x = 7 - 21$ while changing the values on the equals to, the sign of the values or the numbers will change.
Or we can also able to use the subtraction and addition operation, subtract both sides with the number $21$ then we get $21 - x - 21 = 7 - 21$since equal values with opposite signs get cancel each other. Hence we get $ - x = 7 - 21$
Now again making use of the subtraction operation we get $ - x = - 14$ (as mention in the hint, the greater sign stays constant)
Hence canceling the same signs we get $x = 14$ which is the unknown value of the given variable.

Note:
There are four operations. We have seen addition and subtraction in the above problem. The remaining two are multiplication and division. There are two terms in multiplication, they are multiplicand and multiplier. Product is the result of multiplying the multiplicand and multiplier. Division can be referred as the inverse process of multiplication. There are two terms in division, they are dividend and divisor. Hence using simple operations, we solved the given problem.