The number that makes the sum of 21 when added with 12 is 9. Found solving the linear equation x + 12 = 21. Hence, option B is the right choice.
What are linear equations?
Linear equations are relations between two expressions having their degree less than or equal to 1.
How do we solve the given question?
In the question, we are given that the sum of a number and 12 is 21.
We are asked to find the number.
We assume the number to be x.
∴ The sum of a number and 12 is expressed using the expression: x + 12
This expression is equal to 21, which can be represented by the linear equation: x + 12 = 21.
To find x, we solve this linear equation using the given steps:
Equation: x + 12 = 21
Subtract 12 from both sides of the equation: x + 12 - 12 = 21 - 12
∴ x = 9.
∴ The number that makes the sum of 21 when added with 12 is 9. Found solving the linear equation x + 12 = 21. Hence, option B is the right choice.
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