1) 7x-1/5+x=6+3x-7/2
7x-1/5+x=6*2+3x-7/2
7x-1/5+x=3x+5/2
7x-1+x*5/5=3x+5/2
12x-1/5=3x+5/2
24x-2/10=15x+25/10
24x-2=15x+25
24x-2-15x=25
9x-2=25
9x=2+25
9x=27
x=3
b)
(3x-1)^2-8(x-1)^2=(x+2)(x-2)
(3x-1)^2-8(x-1)^2=x^2-2x+2x-4
(3x-1)^2-8(x-1)^2=x^2-4
(3x-1)^2-8(x-1)^2-x^2=-4
9x^2-6x+1-8x^2+16x-8-x^2=-4
x^2-6x+1+16x-8-x^2=-4
-6x+1+16x-8+0=-4
10x+1-8=-4
10x-7=-4
10x=7-4
10x=3
x=3/10
4x+3y=-1
3x-2y=12
4x=-3y-1
3x-2y=12
x=-3y/4-1/4
3x-2y=12
3(-3y/4-1/4)-2y=12
-9y/4-3/4-2y=12
-9y-2y*4/4-3/4=12
-17y/4-3/4=12
-17y/4=3/4+12
-17y/4=51/4
-17y=51/4*4
-17y=51
y=-3
x=9/4-1/4
x=8/4
x=2
(2;-3)
65^2+39^2-52^2-26^2/49^2-2*49*36+36^2
4225+1521-2704-676/2401-3528+1296
2366/169=14
4-(5x-1)²=0;
4-25x²+10x-1=0;
-25x²+10x+3=0;
D=b²-4ac;
D=10²-4*3*(-25)=400;
x1=(-b+√D)/2a;
x2=(-b-√D)/2a;
x1=(-10+20)/2*(-25)=-0,2
x2=(-10-20)/2*(-25)=0,6
Ответ:-0,2; 0,6.
№1
1) 5² * 5⁹ = 5¹¹
2) 2⁸ : 2⁴ = 2⁴
3) (3³)² = 3⁶
4) 4⁸ * 7⁸ = (4 * 7)⁸ = 28⁸
5) (х²)⁵ : х³ = х¹⁰ : х³ = х⁷
№2
1) (5m²y³ + 3m³y² -m) - (3m²y³ +2m + 3m³y²) =
= 5m²y³ + 3m³y² - m - 3m²y³ - 2m - 3m³y² = 2m²y³ - 3m
2) 3x² (b + 2x) - 2x(2b²x + x²) = 3x²b + 6x³ - 4x²b² - 2x³ =
= 3x²b - 4x²b² + 4x³ = x²(3b - 4b² + 4x) = x²(b(3 - 4b) + 4x)
№3
1) (-0.7a³b⁴c²)(-1.8a²bc³) = 1.26(abc)⁵
2)
3) (18x³y³ - 12x⁴y) : (6x³y) = 3y² - 2x
№4
(b³ - b²)(b³ + b²) - (1 + b²)(1 - b² + b⁴) = b⁶ - b⁴ - 1 + b² - b⁴ - b² + b⁴ - b⁶ =
= - 1 - b⁴ = -(1 + b⁴)
- (1 + 0.1⁴) = - (1 + 0,0001) = - 1,0001
№5
х(х + 2) - (х + 3)(х + 1) = 2х + 3
х² + 2х - х² - х - 3х - 3 = 2х + 3
- х - 3х - 3 = + 3
4х = - 6
х = - 1,5
Ответ: - 1,5.