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1)250*20/100=25*2=50
2)60:15*100=400
{y=-x+2
{y=3x
3x=-x+2
4x=2
x=0.5
y=3*0.5
y=1.5
Ответ (0.5;1.5)
(x²+25)/(x-5)(x+5)-5/(x-5)=(x²+25-5x-25)/9x-5)(x+5)=(x²-5x)(x-5)(x+5)=
=x(x-5)(x-5)(x+5)=x/(x+5)
x=15
15/(15+5)=15/20=3/4
А) 0,4^2 * 250^2 = 0.16 * 62500 = 10000
б) 125 * 5^4 / 5^6 = 5^3 * 5^4 / 5^6 = 5^7 / 5^6 = 5