Объяснение:
1)
a) x² - 6x + 5 = 0;
D = 16;
X1 = 5;
X2 = 1;
ответ: 5, 1
б) x² - 5x = 0;
x (x - 5) = 0;
X = 0 или x = 5;
ответ: 0, 5
в) 6x + x²- 7 = 0
x² + 6x - 7 = 0
D=6²-4*1*7=36-28=√8=2√2
x1 = -2√2
x2 = -4√2
ответ: -2√2, -4√2
г) 3x² - 48 = 0
3 (x² - 16) = 0
(x - 4) (x + 4) = 0
x1 = 4
x2 = -4
ответ: 4, -4
2)
S = x (x - 6) = 40
x² - 6x - 40=0
D = 36 + 160 = 196 = 14²
x₁ = (6 + 14) / 2 = 10
x₂ = (6 - 14) / 2 = -4
Длина = 10
Ширина = 10 - 6 = 4
3)
х² + рх - 18 = 0
81 - 9p - 18 = 0
-9p = -63
p = 7
x² + 7x - 18 = 0
x₁ = -9 x₂ = 2
4)
х1 + х2 = -b;
x1 * x2 = c
9 - 4 = 5 b = -5
9 * (-4) = 36 c = -36
х² - 5х - 36 = 0
1)= 5/6+7/12×2/7=5/6+1/6×1/1=5/6+1/6=6/6=1
2)=(24/20-16/20)×2/3=8/20×2/3=2/5×2/3=
=4/15
3)=-6/15-1/2×1/5=-6/15-1/10=-12/30-3/30=
=-15/30=-1/2
4)=15×(1+5/15-3/15)=15×(1+2/15)=15/1×17/15=
=17/1=17
5)=2448/4745+72/73×3/5=2448/4745+
+216/365=2448/4745+216×13/365×13=
=2448/4745+2808/4745=сократить на 39=72/65
6)=-5,8/2,5=-5 8/10÷2 5/10=-58/10×10/25=-58/25=-2 8/25
7)=2 1/10×3 5/10делить на 4,9=21/10×35/10 делить на
4,9=21/2×7/10делить на 4,9=147/20÷4 9/10=147/20×10/49=
=3/2×1/1=3/2=1 1/2=1 5/10=1,5
8)= 1 4/10×2 4/10+ 0,24=14/10×24/10+0,24=7/5×12/5+0,24=
=84/25+24/100=336/100+24/100=360/100=18/5=3 3/5=3,6
