1
(ab+ac)²/(ab²-ac²)=a²(b+c)/a(b²-c²)=a(b+c)/(b-c)(b+c)=a/(b-c)
2
1)1/c-1/(10-c)=(10-c-c)/c(10-c)=(10-2c)/c(10-c)=2(5-c)/c(10-c)=2(c-5)/c(c-10)
2)25/(c-5) -(c-5)=(25-c²+10c-25)/(c-5)=(10c-c²)/(c-5)=c(10-c)/(c-5)
3)2(c-5)/c(c-10) * c(10-c)/(c-5)=-2
<span>а)b^2 - 16=(b-4)(b+4)
б)4a^2 + 12a +9 =(2a+3)</span>²<span>
в)27x^3+ 125=(3x+5)(9x</span>²-15x+25<span>)
г)(-2x-3y)(3x-2y)=-6x</span>²+4xy-9xy+6y²=6y²-6x²-5xy<span>
</span>
m-1/1-m = M-1 / -(M -1) = -1
Пусть они ввстретятся через "х" мин. , тогда:
<span>140х+160х=1000 х=1000:300</span>