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Simplify: 8.4×8.4−2.8×2.85.6×11.2 \frac{8.4 × 8.4 - 2.8 × 2.8}{5.6 × 11.2}5.6×11.28.4×8.4−2.8×2.8​​
Question

Simplify: 8.4×8.42.8×2.85.6×11.2 \frac{8.4 × 8.4 - 2.8 × 2.8}{5.6 × 11.2}

A.

4.2

B.

1

C.

0.5

D.

5.6

Correct option is B

Given
Expression = 8.4×8.42.8×2.85.6×11.2 \frac{8.4 × 8.4 - 2.8 × 2.8}{5.6 × 11.2}​​
Formula Used
a2b2=(ab)(a+b)a^2 - b^2 = (a - b)(a + b)​​
Solution
Numerator = 8.422.828.4^2 - 2.8^2​​
Apply a2b2a^2 - b^2​ formula:
= (8.4 - 2.8) × (8.4 + 2.8)
= 5.6 × 11.2
Substitute back into the expression:
5.6×11.25.6×11.2\frac{5.6 × 11.2}{5.6 × 11.2}​​
= 1

Final Answer
So the correct answer is (b)

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