4x²-3x-1<0
метод интервалов:
1. 4x²-3x-1=0
D=(-3)²-4*4*(-1)=25
x₁=1, x₂=-1/4
4*(x-1)*(x+1/4)=0
2.
+ - +
-------------|-------------|------------ > x
-1/4 1
3.
<u>x∈(-1/4;1)</u> или -1/4<x<1
n² + x + 0.04 = n² + x + 0.2² = n² + 2*n*0.2 + 0.2² = n² + <u>0.4n</u> + 0.4 = (n+0.2)²
n² + x + 0.04 = n² + x + 0.2² = n² + 2*n*(-0.2) + 0.2² = n² - <u>0.4n</u> + 0.4 = (n-0.2)²
Ответ D
I leave my home and walk around the shops.
later, I cross the street. I walk on the bus station which near the supermarket. I come in the bus and go 3 stations. I leave the bus and come to the school
Решать как пропорцию(крест на крест)
получим 1*8х+3=1*11
решаем линейное уравнение.
8х+3=11
8х=11-3
8х=8
х=1
всё)
1)8х-6х-32=6х-4
2)8х-6х-6х=-4+32
3)4х=28
4)х=28/4
5)х=7