Question

Evalute using identity (78)(83)

Answer 1

Answer:

78=80-3

83=80+3

using identity:(a+b)(a-b)=a^2-b^2

(80+3)(80-3)=80^2-3^2

=6400-9

=6391.

Answer 2

Answer:

$\huge\sf{Solution} \:$

$\huge\sf\orange{ 78 \times 83}$

$\sf\purple{ (80 - 2) \times (80 + 3)}$

$\sf\purple{ = 8 {0}^{2} + ( - 2 + 3)80 + ( - 2) \times 3}$

$\sf\purple{ = 6400 + 80 - 6}$

$\sf\purple{ = 6480 - 6 = }\sf\pink{ 6474}$

Using identity :

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

Step-by-step explanation:

i hope it helps you :)

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