1) (1/(2a⁷b⁹)+0,3a⁸b⁶):(1/6a⁵b⁶)=(0.5a⁻⁷b⁻⁹+0,3a⁸b⁶)*6a⁵b⁶= 3a⁻²b⁻³+1,8a¹³b¹²=3/a²b³+1,8a¹³b¹²;
2) (15,2x⁴y¹¹-5,2x³y⁸):(0,2x²y⁷)=76x²y⁴-26xy;
1) = ( 10a^5 )^2 - ( 1/2bc )^2 = 100a^10 - 1/4b^2c^2
2) ( 2y- 3 )( 3y + 1 ) + 2( y - 5 )( y + 5 ) = 2( 1 - 2y^2 ) + 6y
6y^2 + 2y - 9y - 3 + 2( y^2 - 25 ) = 2 - 4y^2 + 6y
6y^2 - 7y - 3 + 2y^2 - 50 = 2 - 4y^2 + 6y
8y^2 - 7y - 53 - 2 + 4y^2 - 6y = 0
12y^2 - 13y - 55 = 0
D = 169 + 2640 = 2809 = 53^2
y1 = ( 13 + 53 ) : 24 = 2,75
y2 = ( 13 - 53 ) : 24 = - 5/3 = - 1 2/3
3) ( 3x - 7 )^2 - 4x^2 = 0
9x^2 - 42x + 49 - 4x^2 = 0
5x^2 - 42x + 49 = 0
D = 1764 - 980 = 784 = 28^2
x1 = ( 42 + 28 ) : 10 = 7
x2 = ( 42 - 28 ) : 10 = 1,4
847.
3(х-14)=2(х-7)
3х-42=2х-14
х=28
848. 11(х-12)=12(х-3)
11х-132=12х-156
156-132=12х-11х
х=24
849. х^2-12=-4х
квадратное уравнение через дискриминант
D=16-4(-12)=64
х1=2;
х2=-6
850. (х^2-12) х=4
х^2-4х-12=0
D=16-4(-12)=16+48=64
х1=12/2=6
х2=-4/2=-2