[tex]1)\\\\15x - 4xy + 8y^2- 5x - 5xy - 40y +6x=- 9 x y + 16 x + 8 y^2 - 40 y\\\\x=2,\ \ \ y=8\\\\- 9 x y + 16 x + 8 y^2 - 40 y=- 9* 2*8+ 16 *2 + 8 *8^2 - 40 *8=\\\\=-144+32+512-320=80[/tex]
[tex]2)\\\\(x + 2y)^2 + (2x - y)^2 - 5(x - y) (x + y)=\\\\=x^2+4xy+4y^2+4x^2-4xy+y^2-5(x^2-y^2)=\\\\= x^2+4xy+4y^2+4x^2-4xy+y^2-5 x^2+5y^2 =10y^2\\\\y=0,1\\\\10y^2=10*(0,1)^2=10*0,01=0,1[/tex]
Odpowiedź:
1)
15x- 4xy + 8y² - 5x - 5xy - 40y + 6x = 16x - 9xy + 8y² - 40y
dla x = 2, y = 8
16 * 2 - 9 * 2 * 8 + 8 * 8² - 40 * 8 = 32 - 144 + 8 * 64 - 320 =
= 32 - 144 + 512 - 320 = 544 - 464 = 80
(x + 2y)² + (2x - y)² - 5 (x - y) * (x + y) =
= x² + 2xy + 2xy+ 4y² + 4x²- 2xy - 2xy + y² - 5x² - 5xy + 5xy + 5y² = 10y²
dla y = 0,1
10y² = 10 * (0,1`)² = 10 * 0,01 = 0,1
Szczegółowe wyjaśnienie:
