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Question
If A = `[(3, 7),(2, 4)]`, B = `[(0, 2),(5, 3)]` and C = `[(1, -5),(-4, 6)]`. Find AB – 5C.
Solution
Given: A = `[(3, 7),(2, 4)]`, B = `[(0, 2),(5, 3)]` and C = `[(1, -5),(-4, 6)]`
Now,
AB = `[(3, 7),(2, 4)][(0, 2),(5, 3)]`
= `[(3 xx 0 + 7 xx 5, 3 xx 2 + 7 xx 3),(2 xx 0 + 4 xx 5, 2 xx 2 + 4 xx 3)]`
= `[(0 + 35, 6 + 21),(0 + 20, 4 + 12)]`
= `[(35, 27),(20, 16)]`
5C = `5[(1, -5),(-4, 6)]`
= `[(5, -25),(-20, 30)]`
AB – 5C = `[(35, 27),(20, 16)] - [(5, -25),(-20, 30)]`
= `[(30, 52),(40, -14)]`
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