-3.5 + 85.95 = 82.45 But how do you get that answer, what do you do?

I don't understand

Do you need to change the sign -/+?

Or do you need to change the negative?

Also if you want to answer this.

What do you do when adding two negatives?

For example, -34.78 + (-29.45)

Please help, Thank you.

Someone answer asap for ! a ball is rolled down a ramp. the height, f(x), in meters, of the ball x seconds after it is released is modeled by the function f(x) = x²- 10x + 25 for all values of x from 0 to 5. which statement about the ball is true? a. the maximum height of the ball is 5 meters b. the height of the ball increases from 0 to 5 meters above the ground. c. the ball has traveled 5 meters when it reaches the bottom of the ramp. d. the ball has been traveling for 5 seconds when it reaches the bottom of the ramp