मराठी

If Δ is an operation such that for integers a and b we have a Δb = a × b – 2 × a × b + b × b (–a) × b + b × b then find (–7) Δ (–1). Also show that (–7) Δ (–1) ≠ (–1) Δ (–7).

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प्रश्न

If Δ is an operation such that for integers a and b we have a Δ b = a × b – 2 × a × b + b × b (–a) × b + b × b then find (–7) Δ (–1). Also show that (–7) Δ (–1) ≠ (–1) Δ (–7).

बेरीज
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उत्तर

We have, a Δ b = a × b – 2 × a × b + b × (b) (–a) × b + b × b

Now, put a = (–7) and b = (–1)

⇒ (–7) Δ (–1) = (–7) × (–1) – 2 × (–7) × (–1) + (–1) × (–1){–(–7)} × (–1) + (–1) × (–1)

=  7 – 14 + 1 × 7 × (–1) + 1

= 7 – 14 – 7 + 1

⇒ –13

Now, put a = (–1) and b = (–7)

⇒ (–1) Δ (–7) = (–1) × (–7) – 2 × (–1) × (–7) + (–7) × (–7){–(–1)} × (–7) + (–7) × (–7)

= 7 – 14 + 49(1) × (–7) + 49

= 7 – 14 – 343 + 49

= –301

Clearly, (–7) Δ (–1) ≠ (–1) Δ (–7)

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पाठ 1: Integers - Exercise [पृष्ठ २१]

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एनसीईआरटी एक्झांप्लर Mathematics Exemplar Class 7
पाठ 1 Integers
Exercise | Q 126. (ii) | पृष्ठ २१

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