Question

Решите пожалуйста. Срочно нужно!!!

Answer 1

1)$x^{2} - 4x -32$ = (х+4)(х-8)
x1 + x2 = 4
х1*х2 = - 32
х1 = 8
х2 = - 4
2)$2x^{2} - 9x + 4$ = (x-4)(x-0.5)
D= 81 - 8 = 72
$\sqrt{D} = 7$
x1 = (9+7)/4 = 4
x2 = (9-7)/4 = 0.5
3)$\frac{ x^{2} + 13x + 40}{ x^{2} +25} = \frac{(x+5)(x+8)}{(x+5)(x-5)} = \frac{(x+8)}{(x-5)}$
4)$( \frac{y}{ y^{2} + 2y -3} - \frac{y-1}{ y^{2} - 9} ) / ( \frac{y+1}{ y^{2} -4y +3} ) = ( \frac{y}{ (y +3)(y -1) } - \frac{y-1}{ (y -3)(y+3)} ) / ( \frac{y+1}{ (y-1)(y-3)} ) =$
$( \frac{y(y-3) - (y-1)(y-1)}{ (y +3)(y -1) } ) * ( \frac{(y-1)(y-3)}{ y+1 } ) = ( \frac{y^{2} - 3y - y^{2} + 2y -1 }{ (y +3)(y -1) } ) * ( \frac{(y-1)(y-3)}{ y+1 } ) =$
$( \frac{ - (y +1) }{ (y +3)(y -1) } ) * ( \frac{(y-1)(y-3)}{ y+1 } ) = - \frac{y-3}{ y+3 }$