Question

31. Expand :
(1) (-3x+5y-2z)square​

Answer 1

Answer:

Step-by-step explanation:

as we know (a + b + c )2 = a2 + b2 + c2 + 2(ab + bc + ca )

-9x2 + 25y2 - 4z2 + 2 ( -15xy - 10 yz + 6xz )

= -9x2 + 25y2 - 4x2 - 30 =xy - 20 yz + 12xz

Answer 2

Answer:

9x² + 25y² + 4z² - 30xy - 20yz + 12xz

Step-by-step explanation:

(-3x+5y-2z)²

= (-3x)² + (5y)² + (-2z)² + 2[{(-3x)(5y)} +

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

= 9x² + 25y² + 4z² + 2(-15xy-10yz+6xz)

Here we used the formula:

(a+b+c)² = a² + b² + c² + 2(ab+bc+ac)

Hope it helps.Thank you!