(x^2 - 1)(x^2 + 3) = (x^2 + 1)^2 + x
x^4<u>+3x^2-x^2</u>-3= (x^4+2x^2+1)+x
x^4+2x^2-3= x^4+2x^2+1+x
<em>x^4+</em><u>2x^2</u>-3-x^4<u>-2x^2-</u>1-x=0
-4-x=0
-x=4
x=-4
Ответ:-4
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9000000000*16.380=147420000000