3х²-2х-1<0
D=4+12=16
x₁=(2-4):6=-2:6=-1/3
х₂=(2+4):6=6:6=1
х∈(-1/3;1)
-2а²+3а+2=0, D=9+16=25, √D=5, a₁=2, a₂= -1/2 ⇒ -2a²+3a+2= -2(a-2)(a+1/2)= -(a-2)(2a+1)
2a²+5a+2=0, D=25-16=9, √D=3, a₁=-2, a₂=-1/2, 2a²+5a+2=2(a+2)(a+1/2)=(a+2)(2a+1)
-(a-2)(2a+1) -a+2
------------------- = ------------
(a+2)(2a+1) a+2
√63=<span>√9*7=3</span>√7 <span>√63<8
</span>√7=2.64
3*2.64=7.93 исходя из ответа √63=3<span>√7</span>
A)50c^2+2(5c-3)^2
50^c2+50c^2-60c+18
100c^2-60c+18
б)(2a+7)(2a-7)-2a(4-2a)
4a^2-14a+14-49
4a^2-49-8a+4a^2
8a^2-8a-49
в)(2x+3)(3-2x)-(2x-5)-10x
-4x+9-4x^2+20x-25-10x
-4x^2+6x-16
<span>a)5х²=25х</span>
<span>5х²-25x=0</span>
5x(x-5)=0
5x=0 или x-5=0
x=0 x=5
<span>б)100х²-16=0</span>
<span>100х²=16</span>
<span>х²=0,16</span>
<span>x=0,4</span>
<span>x=-0,4</span>
<span><span>в)3х²-11х-4=0</span></span>
<span><span>D=121+48=169</span></span>
<span>x1=4</span>
<span>x2=-1/3(дробью)</span>
<span>2.<span>б)3х²-6х деленное на 2(тип дробь)=4-2х</span></span>
<span><span>3х²-6x=4-2x</span></span>
<span><span>3х²-4x+4=0</span></span>
<span><span>D=16+46=64</span></span>
<span><span>x1=2</span></span>
<span><span>x2=-2/3</span></span>