Chapter 3: Q10. (page 150)

If $x = - 2$ , then $15 - 3 (x + 1) =$ ?
$(A) 6 (B) 12 (C) 18 (D) 21$

Short Answer

Expert verified

The option $(C)$ is correct, the other options are incorrect, because the value of the expression $15 - 3 (x + 1)$ when $x = - 2$ is 18.

Step by step solution

– Use the substitution method to find the value of the given expression.

Substitute $x = - 2$ in $15 - 3 (x + 1)$ :

$\begin{matrix} 15 - 3 (x + 1) = 15 - 3 (- 2 + 1) substitute - 2 for x \\ = 15 - 3 (- 1) simplify \\ = 15 + 3 \\ = 18 \end{matrix}$

So, $15 - 3 (x + 1) = 18$ when $x = - 2$ .

– Check whether the option Ais correct or incorrect.

Here, in the option $(A)$ it is given that, 6.

The result in step 1 is $15 - 3 (x + 1) = 18$ .

So, option $(A)$ is incorrect.

– Check whether the option Bis true or false.

Here, in the option $(B)$ it is given that 12.

The result in step 1 is $15 - 3 (x + 1) = 18$ .

So, option $(B)$ is incorrect.

– Check whether the option Cis true or false.

Here, in the option $(C)$ it is given that 18.

The result in step 1 is $15 - 3 (x + 1) = 18$ .

So, option $(C)$ is correct.

– Check whether the option Dis true or false.

Here, in the option $(D)$ it is given that 21.

The result in step 1 is $15 - 3 (x + 1) = 18$ .

So, option $(D)$ is incorrect.

Hence, the option $(C)$ is correct, the other options are incorrect, because the value of the expression $15 - 3 (x + 1)$ when $x = - 2$ is $18$ .

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If $x = - 2$ , then $15 - 3 (x + 1) =$ ?
$(A) 6 (B) 12 (C) 18 (D) 21$

Short Answer

Step by step solution

– Use the substitution method to find the value of the given expression.

– Check whether the option Ais correct or incorrect.

– Check whether the option Bis true or false.

– Check whether the option Cis true or false.

– Check whether the option Dis true or false.

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If x=-2, then 15-3x+1=?A6B12C18D21

Short Answer

Step by step solution

– Use the substitution method to find the value of the given expression.

– Check whether the option Ais correct or incorrect.

– Check whether the option Bis true or false.

– Check whether the option Cis true or false.

– Check whether the option Dis true or false.

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Calculus

Pure Maths

Logic and Functions

Decision Maths

Applied Mathematics

Discrete Mathematics

Study anywhere. Anytime. Across all devices.

If $x = - 2$ , then $15 - 3 (x + 1) =$ ?
$(A) 6 (B) 12 (C) 18 (D) 21$