Question

упростите выражения
1)(x-1)(2)-(x+3)(x-3)

2)(a+1)(a-1)(a(2)+1)-(9+a(2))2, если а=1/3

решите уравнение
(2y-3)(3y+1)+2(y-5)(y+5)=2(1-2y) (2)+6y
​

Answer 1

Ответ:

1) (x-1)(2)-(x+3)(x-3)=x^2 - 2x + 1 - (x^2 - 9) = x^2-2x+1-x^2 + 9 = -2x + 10 

2) (а+1)(а-1)(а²+1)-(9+а²)² = (a²-1)(a²+1) - (9+a²)² = a⁴ -1 - 81 - 18a² - a⁴ = -18a² - 82= -18(1/3)² - 82 = -2 - 82 = -84

3) (2y-3)(3y+1)+2(y-5)(y+5)=2(1-2y)²+6y

6y^2+2y-9y-3+2(y^2+5y-5y-25)=2(1-4y+4y^2)+6y

6y^2-7y-3+2y^2-50=2-8y+8y^2+6y

8y^2-8y^2-55=5y

-55=5y

y=-11

Answer 2

Объяснение:

1

(x-1)^2-(x+3)(x-3)=x^2-2x+1-(x^2-9)=

=x^2-2x+1-x^2+9= - 2x+10

2

(a+1)(a-1)(a^2+1)-(9+a^2)^2=

=(a^2-1)(a^2+1)-(81+18a^2+a^4=

a^4-1-81-18a^2-a^4=

= - 18a^2-82

a=1/3

-18×(1/3)^2-82= - 18×1/9-82=

= - 2-82= - 84

3

(2y-3)(3y+1)+2(y-5)(y+5)=2(1-2y)^2+6y

6y^2+2y-9y-3+2(y^2-25)=2(1-4y+4y^2)+

+6y=

=6y^2+2y-9y-3+2y^2-50=2-8y+8y^2+6y=

=8y^2-7y-53-8y^2+2y=2

-5y=2+53

-5y=55

y= - 11