It is believed that 3/4 of our dreams involve people that we know
a. write an expression to describe the number of dreams that feature people you know if you have d dreams.

Step-by-step explanation:

It is believed that 3/4 of our dreams involve people that we know,

Let there be d dreams.

So, when there are d dreams, the expression to describe the number of dreams that feature people you know is :

In decimal form, it is 0.75d.

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

answer:

c) the x-coordinate of the center of the circle increases by 3