SOLUTION: What is the value of the expression 2x squared + 3xy - 4y squared when x=2 and y=-4?
A. -80
B. 80
C. -32
D. 32
My solution
8+3(2)(-4) - 4(-4) squared
8+(-24)-64
-32-64
Algebra.Com
Question 183960: What is the value of the expression 2x squared + 3xy - 4y squared when x=2 and y=-4?
A. -80
B. 80
C. -32
D. 32
My solution
8+3(2)(-4) - 4(-4) squared
8+(-24)-64
-32-64 = -96
Help me! What am I doing wrong?
Found 2 solutions by stanbon, Alan3354:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
What is the value of the expression 2x squared + 3xy - 4y squared when x=2 and y=-4?
A. -80
B. 80
C. -32
D. 32
---------------------------
2x^2 + 3xy - 4y^2
-------------------------------------
2(2)^2 + 3*2*4 - 4*4^2
= 8 + 24 - 64
= -32
=======================
Cheers,
Stan H.
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
What is the value of the expression 2x squared + 3xy - 4y squared when x=2 and y=-4?
A. -80
B. 80
C. -32
D. 32
My solution
8+3(2)(-4) - 4(-4) squared
8+(-24)-64
-32-64 = -96 ::: 8 + (-24) is -16, not -32 :::
Help me! What am I doing wrong?
----------------------
2x^2 + 3xy - 4y^2
------------
2*4 + 3*2*(-4) - 4*(16)
8 - 24 - 64
= 8 - 88
= -80
RELATED QUESTIONS
If x = –1 and y = 2, what is the value of the expression 2x3 – 3xy ?
A. 8
B. 4
C.... (answered by Alan3354)
If x = –1 and y = 2, what is the value of the expression 2x3 – 3xy ?
A. 8
B. 4
C. (answered by edjones)
What is the value of the expression {{{5x^2y / 5x - y}}} when x = 4 and y = 2?
a)60/3
(answered by itiffydn)
What is the value of the expression {{{ 2x^2 - 5x + 6 }}} when x = -2?
A) -24
B) 4... (answered by stanbon)
The vertex of this parabola is at (2, -4). When the x-value is 3, the
y-value is -1.... (answered by josgarithmetic)
find the value of x and y ..(solution set)
2x squared + 3xy - y squared = 4
x squared (answered by richwmiller)
What is the value of q in this expression when p equals 4?
p squared - qp - 12=0
A. (answered by themathtutor2009)
show me the steps to figure this out.
what is the value of the expression... (answered by Edwin McCravy)
what is the value of the expression of 2x squared plus 3xy minus -4y2 when x = 2 and y =4 (answered by srinivas.g)