Question

14.24. 1) y = (3x - 1) (2x + 5); 3) y = -(2x - 5)(x – 6).2) y = (3x – 6). (0,4 - *);8 класс​

Answer 1

Ответ:

1.  y = (3x - 1) (2x + 5)

y=6x^2+15x-2x-5

y=6x^2+13x-5

y возьмем за 0 и получаем кв. уравнение

6х^2+13x-5=0

D=13^2-4*6*(-5)=289=17^2

X(1)= (-13+17)/12=4/12=1/3

X(2)= (-13-17)/12=-2,5

2.  y = -(2x - 5)(x – 6)

у=-(2х+5)(х-6)

у=-2х^2+12x+5x-30

y=-2x^2+17-30

x(0)=-17\4

y(0)=2*(-17\4)^2+17*17\4+30

x1=0   y=-30

y=0  

-(2x - 5)(x – 6)=0

x=5\2  x=6

Answer 2

It seems like you've provided three different equations:

1. $y = (3x - 1)(2x + 5)$
2. $y = (3x - 6)(0.4 - x)$
3. $y = -(2x - 5)(x - 6)$

These are all quadratic equations in the form of $y = ax^2 + bx + c$, where $a$, $b$, and $c$ are constants.

1. $y = (3x - 1)(2x + 5)$: To simplify this equation, you can use the distributive property to multiply the binomials:

$y = 6x^2 + 15x - 2x - 5$

Now, combine like terms:

$y = 6x^2 + 13x - 5$

2. $y = (3x - 6)(0.4 - x)$: Again, use the distributive property to multiply the binomials:

$y = (3x)(0.4) - (3x)(x) - (6)(0.4) + (6)(x)$

Now, simplify:

$y = 1.2x - 3x^2 - 2.4 + 6x$

Combine like terms:

$y = -3x^2 + 7.2x - 2.4$

3. $y = -(2x - 5)(x - 6)$: Once more, use the distributive property to multiply the binomials:

$y = -(2x)(x) - (2x)(-6) - (-5)(x) - (-5)(-6)$

Simplify:

$y = -2x^2 + 12x + 5x + 30$

Combine like terms:

$y = -2x^2 + 17x + 30$

So, you have simplified forms for all three equations. If you have any specific questions or need further assistance, please let me know.