Question

If$\begin{bmatrix}5x+8 & 7 \\\y+3 & 10x+12 \end{bmatrix}$=$\begin{bmatrix}2 & 3y+1 \\\5 & 0 \end{bmatrix}$then the value of 5x + 3y is equal to:

• A. -1
• B. 8
• C. 2
• D. 0

Answer 1

Answer: (D)

0

Answer 2

Equate corresponding elements of the matrices:$5x + 8 = 2, \quad 10x + 12 = 0, \quad y + 3 = 5, \quad 3y + 1 = 7$

Solve $5x + 8 = 2$:

$5x = -6 \implies x = -\frac{6}{5}$

Solve $3y + 1 = 7$:

$3y = 6 \implies y = 2$

Calculate $5x + 3y$:

$5 \left( -\frac{6}{5} \right) + 3 \cdot 2 = -6 + 6 = 0$