JAMB - Mathematics (1979 - No. 12)
Multiply (3x + 5y + 4z) by (2x - 3y + z)
6x2 + xy - 15y2 + 4z2 + 11xz - 7yz
6x2 + 3xy - 15y2 + 4z2
6x2 + 3xy - y2 + 4z2
6x2 + 3xy - 15y + z2
ব্যাখ্যা
(3x + 5y + 4z)(2x - 3y + z)
6x2 + 9xy + 3x2 + 10xy - 15y2 + 5yz + 8xz - 12yz + 4z2
= 6x2 + xy - 15y2 + 4z2 + 11xz - 7yz
6x2 + 9xy + 3x2 + 10xy - 15y2 + 5yz + 8xz - 12yz + 4z2
= 6x2 + xy - 15y2 + 4z2 + 11xz - 7yz