1) 0,2 * ( - 10 ) = ( - 2 )
2) 0,2 * 5 = 1
Ответ 0,2M ( - 2 ; 1 )
(x+7)(x^2-5x+4)=x(x^2+2x+1)
x^3-5x^2+4x+7x^2-35x+28=x^3+2x^2+x
x^3-5x^2+4x+7x^2-35x+28-x^3-2x^2-x
-32x=-28
x=(-28)/(-32)
x=0,875
D равно минус 4, значит четвёртый равен 1
2cos^2x + (2-<span>√2</span>)sinx+<span>√2</span>-2=0
cos^2x = 1 - sin^2x
2(1 - sin^2x) + (2-<span>√2</span>)sinx+<span>√2</span>-2=0
2-2sin^2x + (2-<span>√2</span>)sinx+<span>√2</span>-2=0
-2sin^2x+(2-<span>√2</span>)sinx+<span>√2</span>=0
2sin^2x-(2-<span>√2</span>)sinx-<span>√2</span>=0
D=(2-<span>√2</span>)^2 + 4*2*<span>√2</span> = 4 - 4<span>√2</span> + 2 + 8<span>√2</span> = 6+4<span>√2</span> = (<span>√2</span>+2)^2
sinx1=(2-<span>√2</span> - <span>√2</span>+2) /4 = (4-2 <span>√2</span>)/4 = (2- <span>√2</span>)/2 = <span>√2</span>/2 ->x=(-1)^(n+1) *pi/4+pi*n
sinx2 = (2-<span>√2</span> +<span>√2</span>+2) /4 = 1 ->x=pi/2+2pi*k
как-то так, проверььте
2x²-12x-59<-3x²-5x-25
2x²+3x²-12x+5x-59+25<0
5x²-7x-24<0
D=49+480=529
x=(7+-23)/10
x1=(7+23)/10=30/10=3
x2=(7-23)/10=-16/10=-1,6
Ответ: (-1,6:3)