Question

Помогите срочно 7 класс

Answer 1

Ответ:

1)

1. (p+q)(p-q)=p²-pq+pq-q²=p²-q²
2. (4+5y)(4-5y)=16-20y+20y-25y²=16-25y²
3. (8c+9d)(9d-8c)=72cd-64c²+81d²-72cd=-64c²+81d²
4. (12a⁴-7x)(-12a⁴-7x)=-144a⁸+84a⁴x-84a⁴x+49x²=-144a⁸+49x²

2)

1. (m+n)²=m²+2mn+n²
2. (b-4)²=b²-8b+16
3. (5-3y)²=25-30y+y²
4. (-2a+b)²=-4a²-4ab+b²

3) (2y+2)²-(y+3)²=3y(y-1)

4y²+8y+4-y²+6y+9=3y²-3y

4y²+8y-y²+6y-3y²-3y=-4-9

11y=13

y=13/11

y=1,2/11