Question

6. Using the identity (a - b)2 = (a2 - 2ab + b2), evaluate the following.
$699^{2}$

$293 ^{2}$
$191 {}^{2}$

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Answer 1

Answer:

1. 488601

2. 85849

3. 36481

Step-by-step explanation:

1.

${699}^{2}$

$by \: using \: identity \: \: = (a - b)^{2} = {a}^{2} - 2ab + {b}^{2}$

$= (700 - 1)^{2}$

$= {700}^{2} - 2(700)(1) + {1}^{2}$

$= 490000 - 1400 + 1$

$= 488601$

2.

$293^{2}$

$= (300 - 7)^{2}$

$= {300}^{2} - 2(300)(7) + {7}^{2}$

$= 90000 - 4200 + 49$

$= 85849$

3.

${191}^{2}$

$= (200 - 9 )^{2}$

$=200^{2} - 2(200)(9) + 9^{2}$

$= 40000 - 3600 + 81$

$= 36481$

Hope I helped You :)

Answer 2

Answer:

293

by using identity

Step-by-step explanation:

• (a-b) square 2 = ( a square 2- 2ab +b square 2)

we know that when we subtract 7 from 300 answer will be the 293.

so, we write

(300 -7) = 293

(a-b) = ( a square 2- 2ab +b square 2)

( 300-7). = ( 300 square 2 - 2 ×300×7 +7 square 2)

293. = ( 90000 - 4200 +49 )( because 300×2-3×300 =600 ×7 = 4200 + 7×7 = 49)

90000-4200 +49

= 85849