2x+2*(1,2-3x)=1,8-2*(x-0,3)
2х+2,4-6х=1,8-2х+0,6
-4х+2,4=2,4-2х
-4х+2х=2,4-2,4
-2х=0
х=0
Проверка:
2*0+2*(1,2-3*0)=1,8-2*(0-0,3)
2*1,2=1,8+0,6
2,4=2,4
Решение
<span>1 ) х </span>²<span> - 16 < 0
x</span>² - 16 = 0
<span>x</span>² = 16
<span>x</span>₁ = - 4
<span>x</span>₂ = 4
<span>- 4 < x < 4
2) х</span>² <span>- 95 < 0
x</span>² - 95 = 0
<span>x</span>² = 95
<span>x</span>₁ = - √95
<span>x</span>₂ = √95
<span>- </span>√95 < x < √95
<span>
3) х</span>²<span> + 1 > 0
x </span>∈ R
![x- \frac{1}{x}= \frac{3}{2}\\ \frac{x^2-1}{x}= \frac{3}{2}\\3x=2(x^2-1)\\2x^2-2x-3x=0\\2x^2-5x=0\\x(2x-5)=0](https://tex.z-dn.net/?f=x-+%5Cfrac%7B1%7D%7Bx%7D%3D+%5Cfrac%7B3%7D%7B2%7D%5C%5C+%5Cfrac%7Bx%5E2-1%7D%7Bx%7D%3D+%5Cfrac%7B3%7D%7B2%7D%5C%5C3x%3D2%28x%5E2-1%29%5C%5C2x%5E2-2x-3x%3D0%5C%5C2x%5E2-5x%3D0%5C%5Cx%282x-5%29%3D0++++)
x=0 или 2x-5=0
2x=5
x=2,5
x≠0 по условию задачи (х в знаменателе)
Ответ: 2,5
1)x+4x=55
5x=55
x=55/5
x=11
2)x+2x=156
3x=156
x=156/3
х=52