Question

Choose the correct description of the graph of the inequality -3x > 15.
Answer

Open circle on -5, shading to the left.

Open circle on 5, shading to the right.

Closed circle on -5, shading to the right.

Closed circle on 5, shading to the left.

Answer 1

since its not greater than and = its definitely not a closed circle

Answer 2

try imagining that the greater than sign is an equal sign. can you solve it now?

Answer 3

-5 to the right?

Answer 4

-5 to the left actually.

so you have -3x > 15.

The best way to do this problem, is to imagine that the greater than sign is a = sign.

-3x = 15

then you solve for x

x = -5

Now consider a number greater than -5, like -4 for example, and put it in the original equation

-3(-4) > 15 --> 12 > 15

which is obviously false, now try the other side (-6)

-3(-6) > 15 --> 18 > 15

which satisfies the equation, therefore we can say that any number less than -5 will fulfill the equation (x < -5)

Alternatively, you can leave the greater than sign in and just solve the equation as normal. However, in the case up multiplying or dividing by negatives, you need to switch the direction of the inequality

Example: -3x > 15 --> -3x (/ -3) > -15 (/ -3) -(Switch the inequality sign) -->

x < -5

which was the original result we obtained

Answer 5

Ok now i understand thanks hunny =)

Answer 6

And its an open cirle right

Answer 7

yes

Answer 8

closed circles are for greater than/less than and equal to. These:
\[\le\]
\[\ge\]