Math (Elementary Algebra)

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

• Math (Elementary Algebra) -

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

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