Question

Wyrażenie (2x+y)²-(x+y)(3x-2y)-3xy doprowadź do najprostszej postaci, a nastepnie oblicz jego wartość dla x=-10 i y=1/3

Answer 1

(2x+y)²-(x+y)(3x-2y)-3xy =4x²+4xy+y²-(3x²-2xy+3xy-2y²)-3xy=
=4x²+4xy+y²-3x²+2xy-3xy+2y²-3xy=x²+3y²
x=-10 i y=1/3
x²+3y²
(-10)²+3(1/3)²=100+3*1/9=100+1/3=100 i 1/3

Answer 2

(2x+y)²-(x+y)(3x-2y)-3xy =4x²+4xy+y²-(3x²-2xy+3xy-2y²)-3xy=
=4x²+4xy+y²-3x²+2xy-3xy+2y²-3xy=x²+3y²
x=-10 i y=1/3
x²+3y²
(-10)²+3(1/3)²=100+3*1/9=100+1/3=100 i 1/3

Answer 3

(2x+y)²-(x+y)(3x-2y)-3xy =
=4x²+4xy+y²-(3x²-2xy+3xy-2y²)-3xy=
=4x²+4xy+y²-3x²+2xy-3xy+2y²-3xy=
=x²+3y²

x=-10
y=1/3
x²+3y²
(-10)²+3(1/3)²=100+3*1/9=100+1/3=100 i 1/3