Question

помогите вариант 1 !)!)!)!)!)!))!))!

Answer 1

1.а)14x²-9x=0;⇒x·(14x-9)=0;
x₁=0;
14x-9=0;⇒14x=9;
x₂=9/14;
б)16x²=49;⇒x²=49/16;
x=⁺₋√(49/16)=⁺₋7/4=⁺₋1,75;
x₁=1,75;x₂=-1,75
в)2x²-11x+12=0
x₁,₂=(11⁺₋√(11²-4·2·12))/4=(11⁺₋√25)/4=(11⁺₋5)/4;
x₁=(11+5)/4=4;
x₂=(11-5)/4=6/4=1,5;
г)x²-36x+324=0;
x₁,₂=18⁺₋√(18²-324)=18⁺₋√0=18;
x=18;
д)2x²+x+16=0
D=1²-4·2·16=1-128=-127;⇒
D<0;-корней нет.
е)(x²-7x)/8  -1=0  ⇒x²-7x-8=0;
x₁,₂=7/2⁺₋√(49/4 +8)=7/2⁺₋√(81/4)=7/2⁺₋9/2;
x₁=7/2+9/2=16/2=8;
x₂=7/2-9/2=-1;
2.   x⁴-13x²+36=0;
x²=y;y>0;⇒y²-13y+36=0;
y₁,₂=13/2⁺₋√((169/4) -36)=13/2⁺₋√(25/4)=13/2⁺₋5/2;
y₁=13/2+5/2=18/2=9;⇒
x²=9;⇒x₁,₂=⁺₋√9
x₁=3;x₂=-3;
y₂=13/2-5/2=8/2=4;
x²=4;⇒x₃,₄=⁺₋√4
x₃=2;x₄=-2;
3.  (6x²-x-1)/(9x²-1)=(9x²-3x²-x-1)/[(3x+1)(3x-1)]=
=[(3x+1)(3x-1)-x(3x+1)]/[(3x+1)(3x-1)]=
=(3x+1)(3x-1-x)/(3x+1)(3x-1)=(2x-1)/(3x-1);
4.  x²+kx+45=0;x₁=5;
x²+px+q=0;
x₁·x₂=q;x₁+x₂=-p;
x₁·x₂=45;⇒x₂=45/5=9;
k=-(x₁+x₂)=-(5+9)=-14;⇒
x²-14x+45=0.

Answer 2

спосибо

Answer 3

спа