Question

use the formula to multiply the following
(x+y) (x-y)​

Answer 1

Answer:

Correct option is

C

(9, 6)

x+y=15 ----- (1)

x−y=3 ----- (2)

First use formula for cross multiplication method:

b

1

c

2

−b

2

c

1

x

=

c

1

a

2

−a

1

c

2

y

=

a

2

b

2

−a

2

b

1

−1

So, from equation (1) and (2) we can write the value of a, b and c.

1×3−(−1)×15

x

=

15×1−1×3

y

=

1×(−1)−1×1

−1

3+15

x

=

15−3

y

=

−1−1

−1

18

x

=

12

y

=

−2

−1

18

x

=

−2

−1

x=

−2

−18

=9

12

y

=

−2

−1

y=

−2

−12

y=6

The solution is (9, 6)

Answer 2

solution=(x+y)(x-y)

using identities (a+b)(a-b)=a^2-b^2

x^2-y^2

this is ans

(Aliter)

(x+y)(x-y)

x(x-y)+y(x-y)

x^2 -xy+xy-y^2 (-xy and +xy is cancelled due to both sign is + and - ,then this sign is put the same value so then ot is cancelled)

x^2-y^2 (-xy+xy is cancelled then ans will get )

i hope it will help you