I meant is -99 rational or irrational?

rational

Step-by-step explanation:

irrational number is number with infinite number behind the dot

ex: 1.11111111111111111111(infinite number 1) is irraltional number

-99 is rational because we can write it as -99/1

A rational number is any number that can be written as a fraction, or ratio, of two whole numbers. The denominator cannot be zero.

Any integer or whole number is rational due to the fact we can just stick it over 1 to form a fraction. The reverse is not true. For example, the fraction 2/3 is rational but it's not a whole number.

answer: 1, 3 and 5 are correct

step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15