rozwiazanie zad w załaczniku... licze na naj:)
[latex]1. -x^2+3x+10geq0 [/latex] [latex]-x^2+3x+10=0[/latex] [latex]delta= b^2-4*a*c[/latex] [latex]delta= 9+4*10= 49[/latex] [latex]sqrt{delta}= 7[/latex] [latex]x_{1}= frac{-b- sqrt{delta}}{2a} x_2= frac{-b+ sqrt{delta}}{2a}[/latex] [latex]x_1=frac{-3-7}{-2}= frac{-10}{-2}=5[/latex] [latex]x_2=frac{-3+7}{-2}=-2[/latex] [latex]x należy <-2,5>[/latex] 2.[latex]x^4-9x^2+20=0[/latex] [latex]x^2=t[/latex] [latex]t^2-9t+20=0[/latex] [latex]delta= 49-4*20=9[/latex] [latex]t_1= frac{9-3}{2}= frac{6}{2}=3[/latex] [latex]t_2=frac{9+3}{2}=frac{12}{2}=6[/latex] [latex]x^2=3 lub x^2=6[/latex] [latex]x=sqrt{3} lub x=-sqrt{3} lub x=-sqrt{6} lub x=sqrt{6}[/latex] 3. 3a-2b=5 a-2b=7 3a-2b=5 a=7+2b 3*(7+2b)-2b=5 21+6b-2b=5 4b=-16 b=-4 a=7+2b a=7-8=-1 a=-1 b=-4 4. 2x+y=3 x-3y=5 y=3-2x x-3*(3-2x)=5 y=3-2x x-9+6x=5 7x=14 x=7 y=3-2x=3-4=-1 x=7 y=-1