What is the value of the expression 2x^2 + 3xy - 4y^2 when x = 2 and y = -4 ?

Question

Please help this is for my accuplacer. If you could show your work explaining how you got the answer that would be awesome. Thank you in advance

Answer 1

2x^2 + 3xy - 4y^2

now substitute your values for every x and y:

2(2^2) + 3(2)(-4) - 4(-4)^2
= 2(4) - 24 - 4(16)
= 8-24-64
= -80

Answer 2

What is the value of –2x2 + 4y if x = –2 and y = 3?

Answer 3

Simplify (2xsquare -3xy square)square