Question

Expand using suitable identity (2x + 5y -3z)2​

Answer 1

Answer:

(2xy+5y)

2

Using,(a+b)

2

=a

2

+b

2

+2ab

=(2xy)

2

+(5y)

2

+2(2xy)(5y)

=4x

2

y

2

+25y

2

+20xy

2

=y

2

(4x

2

+25+20x)

Answer 2

Step-by-step explanation:

Given,

$(2x + 5y -3z) {}^{2}$

we know that

$(a + b + c) {}^{2} = a {}^{2} + b {}^{2} + c {}^{2}  +2ab+2bc +2ca.$

Hence,

$(2x + 5y -3z) {}^{2} = (2x) {}^{2} +(5y) {}^{2} + (- 3z) {}^{2} + 20xy -30yz - 12xz \\ = 4x {}^{2} + 25y {}^{2} + 9z {}^{2} + 2xy - 30yz - 12xz$