Solveit

yes it have

$\text{let s use } (a+b)^2=a^2+2ab+b^2\text{ and }a^2-b^2=(a-b)(a+b):\\x^2 + 3x - 2.5=0\\x^2 + 3x - 2.5+4.75=0+4.75\\x^2 + 3x + 2.25=4.75\text{ (1.5*1.5=2.25 1.5*2=3x)}\\(x+1.5)^2=4.75\\(x+1.5)^2-4.75=0\\(x+1.5-\sqrt{4.75})*(x+1.5+\sqrt{4.75})=0\\x_1=0.679449\\x_2=-3.67945$

:D             

$2x^2+5\\2*(x^2+2.5)$

there is infinitly many solutions

my marks from math is A F A F only :)

Thanks CPhill !

yeah you are right :( but there s need to be another answer more easier 

when you simplifing that it is clearly shown that x=9

$x*\sqrt{x}-10*\sqrt{x}-3=0\\(x-10)*\sqrt{x}-3=0\\(x-10)*\sqrt{x}=3\text{ (square both sides)}\\(x-10)^2*x=9\\ x=9$

$9+\frac{1}{9}=9.1111111111111111$

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