Question

find the following squares by using identities.
1.(b-9)²​ 2.(2xy+6y)²



please answer fast
if you say correct answer I will mark you as brainlest​

Answer 1

Answer:

1 (b-9) ²

Sol. (a-b) ²

: a²-2ab+b²

: (b²)²-2×b×9+(9)²

: b⁴-18b+81b²

2.(2xy+6y) ²

Sol. (a+b) ²

:a²+2ab+b²

: (2xy) ²+2×2xy×6y+(6y) ²

: 4x²y²+24xy²+36y²

Answer 2

Answer:

1.(b-9)^2

• Since, (a-b)^2= a^2 -2ab+b^2
• Therefore,(b-9)^2=(b)^2 - 2×b×9+(9)^2
• = b^2-18b+81 (ans)

2.(2xy+6y)^2

• Since, (a+b)^2=a^2+2ab+b^2
• Therefore, (2xy+6y)^2=(2xy)^2+2×2xy×6y+(6y)^2
• = 4x^2y^2+36y^2+24xy^2(ans)