Question

answer all pls its urgent​

Answer 1

Answer:

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Answer 2

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★ a) Sᴏʟᴜᴛɪᴏɴ :-

Evaluating [ ( - 21 ) + 7 ] + [ 15 + ( - 13 ) ]

➨ [ - 21 + 7 ] + [ 15 - 13 ]

[∵ + ( - ) = - ]

➨ [ - 14 ] + [ 3 ]

➨ - 14 + 3

➨ [ ( - 21 ) + 7 ] + [ 15 + ( - 13 ) ] = - 11

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★ b) Sᴏʟᴜᴛɪᴏɴ :-

Given , angles

• ∠A = 5x - 60°
• ∠B = 2x + 40°
• ∠C = 3x - 80°

As we know that , sum of all angles in a ∆ = 180°. This property is also known as angle sum property.

So ,

⇒ ∠A + ∠B + ∠C = 180°

Substituting the values of angles A , B & C.

⇒ 5x - 60° + 2x + 40° + 3x - 80° = 180°

⇒ 5x + 2x + 3x - 60° + 40° - 80° = 180°

⇒ 10x - 100° = 180°

⇒ 10x = 180° + 100°

⇒ 10x = 280°

⇒ x = 280° ÷ 10

⇒ x = 28°

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