Question

9x(x - 2) – (3x + 5)(3x – 5) При х= -18

Answer 1

Ответ:

349

Пошаговое объяснение:

...=9х^2-18х-(9х^2+15х-15х-25)=

=9х^2-18х-(9х^2-25)=

=9х^2-18х-9х^2+25=

=-18х+25

при х=-18

(-18)*(-18)+25=324+25=349

Answer 2

Ответ:

349

Пошаговое объяснение:

9х (х-2) - (3х+5) (3х-5) = 9х^2 - 18х - (9х^2 - 25) = 9х^ 2 - 18х -9х^2 + 25 = -18х + 25 = (-18)×(-18) + 25 = 324 + 25 = 349

(a+b) (a-b) = a^2 - b^2

Answer 3

To find the value of the expression 9x(x - 2) - (3x + 5)(3x - 5) when x = -18, we can substitute -18 for x and simplify the expression.

Let's plug in x = -18:

9(-18)(-18 - 2) - (3(-18) + 5)(3(-18) - 5)

Simplifying the expression further:

9(-18)(-20) - (-54 + 5)(-54 - 5)

Now, perform the multiplications and additions/subtractions:

3240 - (-49)(-59)

Note: (-49)(-59) is a positive value since multiplying two negative numbers yields a positive result.

3240 - 2881

Finally, subtract:

359

Therefore, when x = -18, the value of the expression 9x(x - 2) - (3x + 5)(3x - 5) is 359.