Question

Expand:- (-5x + 7y - 3z)²

Answer 1

$[ +(-5x)+7y + (-3z) ]^2$

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By Formula $(a+b+c)^2 = a^2 +b^2 +c^2 +2(ab +bc+ca)$
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$= [ (-5x)^2 + (7y)^2 + (-3z)^2 + 2[(-5x * 7y)+(7y * -3z)+(-3z*-5x)$

= [tex]25x^2 + 49y^2 + 9z^2 + 2[-35xy - 21yz + 15zx] [/tex]



= $25x^2 + 49y^2 + 9z^2 - 70xy -42yz + 30zx$


i hope this will help you


-by ABHAY

Answer 2

Hey there!

Expression in the form of Identity
(x+y+z)³ = x²+y²+z²+2xy+2xz+2yz

x = -5x
y = 7y
z = -3z

(-5x)² + (7y)² + (-3z)² + 2 (-5x) (7y) + 2 (-5x) (-3z)+ 2 (7y) (-3z)

= 25x² + 49y² + 9z² - 70xy + 30xz - 42yz

(Also refer attachment if it's understandable XD)

Hope helped.
:)