1/9х-1/8х=-4-2
8-9/72х=-6
-1/72х=-6
1/72х=6
х= 6÷1/72=6×72
х=432
Вот, впринципе, ничего сложного
x^2-y=3 x=3-y x=3-y x=3-y [x= √3
x+y=3 (3-y)^2-y=3 9-6y+y^2-3=0 y^2-6y+6=0 { [ y=3- √3
[x=- √3
[y=3+ √3
y^2-6y+6=0
<span>D</span><span> = b</span>2<span> - 4ac = (-6)</span>2<span> - 4∙1∙6 = 12</span>
<span>D</span><span> > 0 ⇒ уравнение имеет 2 корня</span>
<span>y = -b ± √D / 2a</span>
<span>y1</span><span> = (6 - √12) / (2∙1) = 3- √3</span>
<span>y2</span><span> = 3+ √3</span>
Парабола, ветви вниз т.к. a<0
1) x² + 8x + 7 > 0
(x + 7)( x + 1) > 0
+ - +
_____₀________₀______
- 7 - 1
x ∈ (- ∞ ; - 7)∪(- 1 ; +∞)
2) x² - 8x + 16 > 0
(x - 4)² > 0
+ +
_______₀____________
4
x ∈ ( - ∞ ; 4)∪(4 ; + ∞)