Question

5х-18=4х;   х(х+9)=(х+3)(х-3)

Answer 1

5х-18=4х
5х-4х=18
х=18


х(х+9)=(х+3)(х-3) 
 x^{2}  - 9х =  x^{2} -9
x^{2}- x^{2}  - 9х=-9
х в квадрате сокращается и остается 
-9х=-9
х=1

Answer 2

To solve the equation 5x - 18 = 4x, we can start by subtracting 4x from both sides of the equation:

5x - 4x - 18 = 4x - 4x

Simplifying, we get:

x - 18 = 0

Next, we add 18 to both sides of the equation:

x - 18 + 18 = 0 + 18

This gives us:

x = 18

To solve the equation x(x + 9) = (x + 3)(x - 3), we can start by expanding both sides:

x^2 + 9x = x^2 + 3x - 3x - 9

Simplifying, we get:

x^2 + 9x = x^2 - 9

Next, we subtract x^2 from both sides of the equation:

x^2 + 9x - x^2 = x^2 - 9 - x^2

Simplifying further, we have:

9x = -9

Now, we divide both sides of the equation by 9:

9x/9 = -9/9

This simplifies to:

x = -1

So the solution to the equation x(x + 9) = (x + 3)(x - 3) is x = -1.