(а - в)(а + в) = 68*72
а - в = 68 а = 68 + в а = 68 + в а = 68 +в а=70
а + в = 72 68+в + в = 72 2в =72 - 68 в = 2 в =2
(70 - 2)(70+2) = 70² - 2² = 4900 - 4 = 7896
240/x-240/(x-5)+4=0
x(x-5)≠0⇒x≠0,x≠5
240(x-5)-240*x+4x(x-5)
240x-1200-240x+4x²-20x=0
4x²-20x-1200=0
x²-5x-300=0
x1+x2=5 U x1*x2=-300
x1=-15 U x2=20
<span>1) 5√2 - 11√2 + 67√2 = (5 - 11 + 67)</span>√2 = 63√2.<span>
2) -8√7+20√7-22√7 = (-8 + 20 - 22)</span>√7 = -10√7.<span>
3) 14√3-√3-10√3 = (14 - 1 - 10)</span>√3 = 3√3.<span>
4) -20√13+18√13-2√13 = (- 20 + 18 - 2)</span>√13 = - 4√13.<span>
5) 4√а+5√b-7√a = (4 - 7)</span>√a + 5√b = - 3√a + 5√b.<span>
6) 0.3√x+0.2√y+0.6√x = (0,3 + 0,6)</span>√x + 0.2√y = 0,9√x + 0,2√y<span>
7) √a - √b + 29√a - √b = (1 + 29)</span>√a - (1 + 1)√b = 30√a - 2√b.<span>
8) 48√x+2√x-2√y-50√x = (48 + 2 - 50)</span>√x - 2√y = 0·√x - 2√y = 0 - 2√y = - 2√y.
|3x+2|-1=3, ⇒ 3х+2-1=3 и -3х-2-1=3
3х+1=3 -3х-3=3
3х=2 -3х=6
х=2/3 х=-2
∑=2/3+(-2)=-1 1/3