Question

If x = 3 and y = -1, then 3x2 + 2xy - 5 = ?
A: 18
B: 24
C: 12
D: 16

Answer 1

`3\cdot3^2+2\cdot3\cdot(-1)-5=27-6-5=16`

Answer 2

`x = 3 , \ y = -1 \\ \\ 3x^2 + 2xy - 5 = 3\cdot 3^2 + 2\cdot 3\cdot (-1)-5=\\ \\=3\cdot 9 -6-5=27-11=16 \\ \\ Answer : \ D: \ \ 16`