Find the values of a, b, c and d from the following equations:
Find the values of a, b, c and d from the following equations:

RD Sharma Solutions for Class 12 Maths Chapter 5 Image 132

Solution:

RD Sharma Solutions for Class 12 Maths Chapter 5 Image 133

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

Given that two matrices are equal.

Therefore by equating them we get,

\[2a\text{ }+\text{ }b\text{ }=\text{ }4~\ldots \ldots ~\left( 1 \right)\]

And \[a\text{ }-\text{ }2b\text{ }=\text{ }\text{ }3~\ldots \ldots \text{ }\left( 2 \right)\]

And \[5c\text{ }-\text{ }d\text{ }=\text{ }11~\ldots \ldots ~\left( 3 \right)\]

\[4c\text{ }+\text{ }3d\text{ }=\text{ }24~\ldots \ldots ~\left( 4 \right)\]

Multiplying equation \[\left( 1 \right)\text{ }by\text{ }2\] and adding to equation (2)

\[4a\text{ }+\text{ }2b\text{ }+\text{ }a\text{ }-\text{ }2b\text{ }=\text{ }8\text{ }-\text{ }3\]

\[\Rightarrow ~5a\text{ }=\text{ }5\]

\[\Rightarrow ~a\text{ }=\text{ }1\]

Now, substituting the value of a in equation (1)

\[2\text{ }\times \text{ }1\text{ }+\text{ }b\text{ }=\text{ }4\]

\[\Rightarrow ~2\text{ }+\text{ }b\text{ }=\text{ }4\]

\[\Rightarrow ~b\text{ }=\text{ }4\text{ }-\text{ }2\]

\[\Rightarrow ~b\text{ }=\text{ }2\]

Multiplying equation \[\left( 3 \right)\text{ }by\text{ }3\] and adding to equation (4)

\[15c\text{ }-\text{ }3d\text{ }+\text{ }4c\text{ }+\text{ }3d\text{ }=\text{ }33\text{ }+\text{ }24\]

\[\Rightarrow ~19c\text{ }=\text{ }57\]

\[\Rightarrow ~c\text{ }=\text{ }3\]

Now, substituting the value of \[c\] in equation (4)

\[4\text{ }\times \text{ }3\text{ }+\text{ }3d\text{ }=\text{ }24\]

\[\Rightarrow ~12\text{ }+\text{ }3d\text{ }=\text{ }24\]

\[\Rightarrow ~3d\text{ }=\text{ }24\text{ }\text{ }12\]

\[\Rightarrow ~3d\text{ }=\text{ }12\]

\[\Rightarrow ~d\text{ }=\text{ }4\]

\[\therefore ~a\text{ }=\text{ }1,\text{ }b\text{ }=\text{ }2,\text{ }c\text{ }=\text{ }3\text{ }and\text{ }d\text{ }=\text{ }4\]