5)
0.4х=-0.44
х=-0.44÷0.4
х=-1.1
6)
1/3х+1/9х=2/7-5/7
3/9х+1/9х=-3/7
4/9х=-3/7
х=-3/7÷4/9
х=-3/7×9/4=-27/28
7)
12а+15=17а-5
17а-12а=15+5
5а=20
а=4
4)
номер 4
log3 x- log9 x+log81 x=3/4
ОДЗ x>0
log3 x - log3^2 x + log 3^4 x =3/4
log3 x -1/2 log3 x + 1/4 log x=3/4
log3 x (1-1/2+1/4)=3/4
3/4 log3 x=3/4
log3 x=1
<span>x=3
</span>
X и 15-x
x(15-x)
y=x(15-x)=15x-x^2
y'=15-2x
y'=0
15-2x=0
2x=15
x=7.5 - точка минимума
15-х=15-7,5=7,5
эти числа 7,5 и 7,5
Ответ:
<h3>
<em>См</em><em>отрите</em><em> вложение</em><em>.</em></h3>
<em>~•~•~•ZLOY_TIGROVSKIY~•~•~•</em>
1) 1. -2x(1-x)+(2x-3)(x-1)=-2x+2x^2+2x^2-2x-3x+3=4x^2-7x+3
2. 4(1+3x)^2-24x=4(1+6x+9x^2)-24x=4+24x+36x^2-24x=36x^2+4=4(9x^2+1)
3. (x+4)(x-4)-(x-3)^2=x^2-16-(x^2-6x+9)=x^2-16-x^2+6x-9=6x-25
2)1. y-100y^3=y(1-100y^2)=y(1-10y)(1+10y)
2. 7a^2-14ab+7b^2= 7a^2-7ab-7ab+7b^2=(7a^2-7ab)+(-7ab+b^2)=7a(a-b)-7b(a-b)=(a-b)(7a-7b)=7(a-b)(a-b)
4)xy^2-x+5-5y^2=(xy^2-x)+(5-5y^2)=x(y^2-1)-5(y^2-1)=(y^2-1)(x-5)