Question

find the values using expansion formula : 2.3 ×2.7
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Answer 1

We have:

2.3 × 2.7

We have to find the value of 2.3 × 2.7 using expansion formula.

Solution:

∴ 2.3 × 2.7

= (2 + 0.3)(2 + 0.7)

Using expansion formula:

(x + a)(x + b) = $x^{2}$ + (a + b)x + ab

Here, x = 2, a = 0.3 and b = 0.7

= $2^{2}$ + (0.3 + 0.7)x + (0.3)(0.7)

= 4 + (1)2 + 0.21

= 4 + 2 + 0.21

= 6 + 0.21

= 6.21

∴ 2.3 × 2.7 = 6.21

Thus, the value of 2.3 ×2.7 using expansion formula is 6.21.

Answer 2

SOLUTION

TO DETERMINE

The values using expansion formula :

2.3 × 2.7

FORMULA TO BE IMPLEMENTED

We are aware of the formula that

$\sf{ {a}^{2} - {b}^{2} = (a + b)(a - b) }$

EVALUATION

$\sf{2.3 \times 2.7}$

$\sf{ = (2.5 - 0.2) \times (2.5 + 0.2)}$

$\sf{ = {(2.5)}^{2} - {(0.2)}^{2} } \: \: \: \:( using \: above \: formula)$

$\sf{ = 6.25 - 0.04}$

$= \sf{6.21}$

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