Chapter 4: Q36. (page 158)

What is the value of $y$ if $[\begin{matrix} 3 x \\ y + 5 \end{matrix}] = [\begin{matrix} 9 + y \\ x \end{matrix}]$ ?
A. 2 B. 4 C. $- 3$ D. localid="1648213664321" $- 1$

Short Answer

Expert verified

The value of y is $- 3$ .

Step by step solution

– Description of step.

As the matrices are equal, the corresponding elements are equal. Write the two linear equations to show this equality.

\begin{matrix} 3 x = 9 + y \\ y + 5 = x \end{matrix}

– Description of step.

Substitute $y + 5$ for x into $3 x = 9 + y$ and simplify.

\begin{matrix} 3 (y + 5) = 9 + y \\ 3 y + 15 = 9 + y \\ 3 y - y = 9 - 15 \\ 2 y = - 6 \end{matrix}

– Description of step.

Divide each side of $2 y = - 6$ by 2 to find the value of $y$ .

\begin{matrix} \frac{2 y}{2} = \frac{- 6}{2} \\ y = - 3 \end{matrix}

Therefore, option C is the correct answer.

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What is the value of $y$ if $[\begin{matrix} 3 x \\ y + 5 \end{matrix}] = [\begin{matrix} 9 + y \\ x \end{matrix}]$ ?
A. 2 B. 4 C. $- 3$ D. localid="1648213664321" $- 1$

Short Answer

Step by step solution

– Description of step.

– Description of step.

– Description of step.

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What is the value of yif 3xy+5=9+yx?A. 2 B. 4 C. -3 D. localid="1648213664321" -1

Short Answer

Step by step solution

– Description of step.

– Description of step.

– Description of step.

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Discrete Mathematics

Mechanics Maths

Statistics

Applied Mathematics

Geometry

Theoretical and Mathematical Physics

Study anywhere. Anytime. Across all devices.

What is the value of $y$ if $[\begin{matrix} 3 x \\ y + 5 \end{matrix}] = [\begin{matrix} 9 + y \\ x \end{matrix}]$ ?
A. 2 B. 4 C. $- 3$ D. localid="1648213664321" $- 1$