Х^2-4х-5=0
D= 16+20=6^2
х1= 5
х2=-1
А1.
(√(6-t) + √(5-t))² =4²
6-t+2<span>√[(6-t)(5-t)]+5-t=16
2</span>√(30-5t-6t+t²<span>)=2t+16-11
(2</span>√(t²-11t+30))²=(2t+5)²
4(t²-11t+30)=4t²+20t+25
4t²-4t²-44t-20t=25-120
<span>-64t=-95
t=95/64
</span>√(6-t) - √(5-t)=√(6 - ⁹⁵/₆₄) - √(5 - ⁹⁵/₆₄)=√(²⁸⁹/₆₄) - <span>√(</span>²²⁵/₆₄<span>)=
</span><span>= </span>¹⁷/₈ - ¹⁵/₈ = ²/₈ = ¹/₄ = 0.25
<span>Ответ: 1)
А2.
[5(x+2)+1]/[(x+2)-4] - [5(x+6)+1]/[(x+6)-4]=
=(5x+10+1)/(x-2) - (5x+30+1)/(x+2)=
=(5x+11)(x-2) - (5x+31)/(x+2) =
=[(5x+11)(x+2)-(5x+31)(x-2)]/(x</span>² -4<span>)=
=(5x</span>²+11x+10x+22-5x²-31x+10x+62<span>)/(x</span>² -4<span>)=
=84/(x</span>² -4<span>)
Ответ: 1)
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