D(f): 7-2x>0;
2x<7; x<7/2 ; x<3,5.
/////////(3,5)-------→x
ответ : D(f) = (-oo;3,5).
6x^2+5x-20+9=0<span>
6x^2+5x-11=0
Д= 25+264=289=17^2
X1= -5+17/12= -1
X2= -5-17/12= -11/6
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1) (2a+b)^2 2) (0,2x-y)^2
3) (5a-3x)^3 4)
5) (3ab-x) (3ab+x) 6) (-x-2y) (-x+2y)
7) (0,2p+q) (q-0,2) 8) (3-a) (9+3a+a^2)
<span>9) (2x+3y) (4x^2-6xy+9y^2)fda</span>
3xy - 6y -
+ 2x = 3 * 2 * (-
) - 6 * (-
) + 4 + 4 = - 2 - 2 + 4 + 4 = 4
2/(x-1)(x+1)+1/(x+1)=(2+x-1)/(x-1)(x+1)=(x+1)/(x-1)(x+1)=1/(x-1)
1/(x-1)*x(x-1)=x
3)x-x=0