Question
Download Solution PDFSimplify (5z - 7y)2 + (7z + 5y)2 - 49z2
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFGiven:
Simplify (5z - 7y)2 + (7z + 5y)2 - 49z2
Formula used:
(a + b)2 = a2 + 2ab + b2
(a - b)2 = a2 - 2ab + b2
Calculation:
(5z - 7y)2 + (7z + 5y)2 - 49z2
⇒ (25z2 - 2 × 5z × 7y + 49y2) + (49z2 + 2 × 7z × 5y + 25y2) - 49z2
⇒ 25z2 - 70zy + 49y2 + 49z2 + 70zy + 25y2 - 49z2
⇒ 25z2 + 49z2 - 49z2 + 49y2 + 25y2
⇒ 25z2 + 74y2
∴ The correct answer is option (4).
Last updated on Jul 21, 2025
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