1)а) (15ab - 7b) - (ab + 3b) = 15ab - 7b - ab - 3b = 14ab - 10b
б) 7x • (4x^2 - 3x - 6) = 28x^3 - 21x^2 - 42x
2)а) (b - 4)(b + 5) = b^2 + 5b - 4b - 20 = b^2 + b - 20
б) (6x + 7)(3x - 1) = 18x^2 - 6x + 21x - 7 = 18x^2 + 15x - 7
в) (3y - 4a)(5y - 2a) = 15y^2 - 6ay - 20ay + 8a^2 = 15y^2 - 26ay + 8a^2
г) (b - 2)(b^2 + 3b - 4) = b^3 + 3b^2 - 4b - 2b^2 - 6b + 8 = b^3 + b^2 - 10b + 8
3)7 - 4(3x - 1) = 5(1 - 2x)7 - 12x + 4 = 5 - 10x11 - 12x = 5 - 10x11 + 5 = 12x - 10x16 = 2xx = 8
1)
а) (15ab - 7b) - (ab + 3b) = 15ab - 7b - ab - 3b = 14ab - 10b
б) 7x • (4x^2 - 3x - 6) = 28x^3 - 21x^2 - 42x
2)
а) (b - 4)(b + 5) = b^2 + 5b - 4b - 20 = b^2 + b - 20
б) (6x + 7)(3x - 1) = 18x^2 - 6x + 21x - 7 = 18x^2 + 15x - 7
в) (3y - 4a)(5y - 2a) = 15y^2 - 6ay - 20ay + 8a^2 = 15y^2 - 26ay + 8a^2
г) (b - 2)(b^2 + 3b - 4) = b^3 + 3b^2 - 4b - 2b^2 - 6b + 8 = b^3 + b^2 - 10b + 8
3)
7 - 4(3x - 1) = 5(1 - 2x)
7 - 12x + 4 = 5 - 10x
11 - 12x = 5 - 10x
11 + 5 = 12x - 10x
16 = 2x
x = 8