Zad 17. Wykonaj działania
a)(m+n)(m-2)-(m-n)(m+1)=
b)(3x-2)(3x-2y+1)-4x(2x-3y+1)
c)3(m+1)(n-2)+2(n+1)(x-2)

Zad 18. Oblicz wartosci liczbowe podanych sum algebraicznych dla x = -1, i y = 0,1
a)4(5y+1)(1-5y)-5(4x+1)(1-4x)
b)(x+2y)kwadrat + (2x-y)kwadrat -5(x-y)(x+y)
c)3y(3y-2x)-(3-x)(x+3)-(x-3y)kwadrat

1

Odpowiedzi

2009-12-03T18:55:28+01:00
17
a)=m²-2m+mn-2n-m²-m+mn+n=-3m+2mn-n
b)=9x²-6xy+3x-6x+4y-2-8x²+12xy-4x=x²-7x+6xy+4y-2
c)=3(m²-2m+n-2)+2(xn-2n+x-2)=3m²-6m+3n-6+2xn-4n+2x-4=3m²-6m-n-10+2xn+2x
18
a)=4(5y-25y²+1-5y)-5(4x-16x²+1-4x)=20y-100y²+4-20y-20x+80x²-5+20x=-100y²+80x²-1
-100y²+80x²-1=-100*(0,1)²+80*(-1)²-1=80-1-1=78
b)=x²+4xy+4y²+(4x²-4xy+y²)-5x²+5y²=x²+4xy+4y²+4x²-4xy+y²-5x²+5y²=10y²
10y²=10*(0,1)²=10*1/100=1/10
c)=9y²-6xy-(3x+9-x²-3x)-(x²-6xy+9y²)=9y²-6xy-3x-9+x²+3x-x²+6xy-9y²=-9