1.

If \(\begin{bmatrix}2x+1 & 5x \\[0.3em]0 & y^2+1 \\[0.3em]\end{bmatrix}​​\) = \(\begin{bmatrix}x+3 & 10 \\[0.3em]0 & 26 \\[0.3em]\end{bmatrix},​​\)find the value of (x + y).

Answer»

Given two matrices are equal.

\(\begin{bmatrix}2x+1 & 5x \\[0.3em]0 & y^2+1 \\[0.3em]\end{bmatrix}​​\) = \(\begin{bmatrix}x+3 & 10 \\[0.3em]0 & 26 \\[0.3em]\end{bmatrix}​​\)

We know that if two matrices are equal then the elements of each matrices are also equal.

∴2x + 1 = x + 3 … (1) 

⇒ 2x – x = 3 – 1 

⇒ x = 2

And 5x = 10 … (2)

y2 + 1 = 2   … (3)

⇒ y2 = 26 – 1 

⇒ y2 = 25 

⇒ y = 5 or – 5

∴ x = 2, y = 5 or – 5 

∴ x + y = 2 + 5 = 7 

Or x + y = 2 – 5 = – 3



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