Question

УМНИКИ АЛГЕБРЫ,СЛУШАЙТЕ С: 1.Выполните действия: а)(3а^2-а)●(-а) б)6х(3-х)-2х(х+9) 2.Вынесите общий множитель за скобки: а)3ху+6ау б)у^3-y^4 3.Задача. В трёх классах 30 мальчиков.В 7-А на 3 мальчика больше,чем в 7-Б,а в 7-В столько,сколько в 7-А и 7-Б вместе.Сколько мальчиков в каждом классе? ПОСТАРАЙТЕСЬ:ззз

Answer 1

1. а) -3а^3+а^2
б) 18x-6x^2-2x^2+18x=4x^2+36

2.a) 3y(x+3a)
б) y^3( 1-y)

3. x- количество мальчиков в 7Б
x+3- количество мальчиков в 7А
x+x+3- количество мальчиков в 7В

1). х+х+3+х+х+3=30
4х+6=30
4х=30-6
4х=24
х=24:4
х=6(м.) - учится в 7Б

2). 6+3=9 (м) - учится в 7А

3). 6+6+3=15(м) учится в 7В
Ответ: в 7А учится 9 мальчиков, в 7Б - 6 мальчиов, в 7В - 15 мальчиков

Answer 2

2. а)3y(x+2a); б) y^3(1-y)

Answer 3

Algebraic Operations

a) To perform the given multiplication: (3a^2 - a) * (-a)

We can use the distributive property to multiply each term in the first expression by the second expression and then combine like terms.

The result of the multiplication is: -3a^3 + a^2

b) For the expression: 6x(3-x) - 2x(x+9)

We can factor out the common terms from each expression.

The factored expression is: 6x(3-x) - 2x(x+9) = 18x - 6x^2 - 2x^2 - 18x = -8x^2 + 18x

Factoring Expressions

a) To factor the expression: 3hu + 6au

We can factor out the common term '3u' from both terms.

The factored expression is: 3u(h + 2a)

b) For the expression: u^3 - y^4

This expression cannot be factored further as it is a difference of two perfect squares.

Problem Solving

The problem states that there are 30 boys in three classes, with 7-A having 3 more boys than 7-B, and 7-C having the same number of boys as 7-A and 7-B combined.

Let's denote the number of boys in 7-B as 'x'. Then the number of boys in 7-A is 'x + 3', and the number of boys in 7-C is '2x + 3'.

Given that the total number of boys in all three classes is 30, we can form the equation: x + (x + 3) + (2x + 3) = 30

Solving this equation will give us the number of boys in each class.

I hope this helps! If you have any further questions or need additional assistance, feel free to ask.