A^2-8a-33=a^2-8a+16-49=(a-4)(a-4)-49=(a-4)^2-49=(a-4-7)(a-4+7)=(a-11)(a+3)
y= - x²-x+9
y=f(x)
1) f(2)= - 2²-2+9=3;
f(2)=3
2) f(-3)= - (-3)²-(-3)+9= -9+3+9 = 3;
f(-3)=3
3) (k;3)
x=k;
y= 3;
3 = -k² -k +9;
k² + k - 6 =0
D=1-4·1·(-6) = 1+24 = 25 = 5²
k₁ = (-1-5)/2= -3
k₂ = (-1+5)/2= 2
k₁ = -3
k₂ = 2
(5/6 + м)(5/6 - м) = 25/36 - м^2
(к + 1,1)(к- 1,1) = к^2 - 1,21
(2x+5)²- (2x-3)(2x+1)=4
4x²+20x +25 - (4x²+2x-6x-3)=4
4x²+20x+25-4x²+4x+3=4
24x+28=4
24x=4-28
24x= -24
x=-1
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(2*(-1)+5)²-(2*(-1) -3)(2*(-1)+1)=4
3²- (-5) * (-1)=4
9- 5=4
4=4