X + 2 Y + 4 Z Square factorise
Answers
Answer:
hand side expression.
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Solution:
i)
(x + 2y +
4z)²
Using identity,
(a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca
Here, a = x, b = 2y and c = 4z
(x + 2y + 4z)²
= x² + (2y)² +
(4z)²² + (2×x×2y) + (2×2y×4z) + (2×4z×x)
= x² +
4y² + 16z²+ 4xy + 16yz + 8xz
(ii) (2x – y + z)²
Using identity,
(a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca
Here, a = 2x, b = –y & c
= z
(2x – y + z)²
= (2x)² +
(-y)² + z² + (2×2x×-y) + (2×-y×z) +
(2×z×2x)
= 4x² + y² + z² –
4xy – 2yz + 4xz
(iii) (–2x +
3y + 2z)²
Using identity=
(a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca
Here, a = -2x, b = 3y & c
= 2z
(–2x + 3y + 2z)²
= (-2x)² + (3y)²+
(2z)² + (2×-2x×3y) + (2×3y×2z)+ (2×2z×-2x)
= 4x² + 9y² + 4z² –
12xy + 12yz – 8xz
(iv) (3a –
7b – c)²
Using identity,
(a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca
Here, a = 3a, b,= -7b &c = -c
(3a – 7b – c)²
= (3a)² +
(-7b)²+ (-c)² + (2×3a×-7b) +
(2×-7b×-c) + (2×-c×3a)
= 9a² + 49b² + c² –
42ab + 14bc – 6ac
(v) (–2x +
5y – 3z)²
Using identity,
(a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca
Here, a = -2x, b = 5y and c = -3z
(–2x + 5y – 3z)²
= (-2x)² + (5y)² +
(-3z)² + (2×-2x×5y) + (2×5y×-3z) + (2×-3z×-2x)
= 4x² + 25y² + 9z²–
20xy – 30yz + 12xz
(vi) [1/4 a –
1/2 b + 1]²
Using identity,
(a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca
Here, a = a/4 , b = -b/2
& c = 1
[1/4 a – 1/2 b + 1]²
=(a/4)²+(-b/2 )²+1²+
(2×a/4 ×-b/2)+(2×-b/2 ×1) + (2×1×a/4)
= a²/16+ b²/4+ 1 – ab/4– b + a/2
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