Engineering Board Exam Reviewer · Matrix Operations · medium

Given A= bmatrix1&0&2\-1&3&1 bmatrix and B= bmatrix2&1\0&-1\4&3 bmatrix, find AB.

1. bmatrix10&7\2&-1 bmatrix
2. bmatrix10&2\7&-1 bmatrix
3. bmatrix10&7\2&1 bmatrix
4. bmatrix10&5\2&-1 bmatrix

Answer

A. bmatrix10&7\2&-1 bmatrix

Solution

Each entry is a row of A times a column of B: AB= bmatrix10&7\2&-1 bmatrix. For example, the top-left entry is 1(2)+0(0)+2(4)=10.

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