The algebraic expression 25x2 + 16y2 + 9z2 - 40xy + 24yz - 30zx is equal to:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. (4y + 3z - 5x)2.
25x2 + 16y2 + 9z2 - 40xy + 24yz - 30zx
= (-5x)2 + (4y)2 + (3z)2 + 2(-5x)(4y) + 2(4y)(3z) + 2(3z)(-5x)
= (4y + 3z - 5x)2