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Question
If x = 2, y = 3 and z = 4, find the value of 3x2 – 4y2 + 2z2.
Sum
Solution
x = 2, y = 3, z = 4
∴ 3x2 − 4y2 + 2z2
= 3 (2)2 − 4 (3)2 + 2 (4)2
= 3 × 4 − 4 × 9 + 2 × 16
= 12 − 36 + 32
= 12 + 23 − 36
= 44 − 36
= 8
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Concept of Substitution
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