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I really need to get my Algebra grade up and i need help with some of these problems here's one:

-12-d>-12+4d

Hi Hannah, I will be glad to help.

Solving inequalities is exactly like solving equations with 1 difference:

If you need to multiply or divide both sides of the inequality by a negative number, flip the inequality

Here's an example of the rule above

-2m < 16

Because you must divide both sides by -2, the inequality sign. Must be flipped, or changed from < to >

The solution here would be

m > -8

With your problem

-12 - d > -12 + 4d

Bring the variable to the left side by subtracting 4d from both sides to get

-12 - 5d > -12

Since we grouped the variables on the left side of the inequality, we want to group all the constants (numbers without variables) on the right.

To get rid of the -12 on the left, add 12 to both sides (since -12 + 12 = 0 )

-5d > 0

Notice adding 12 does not change the sign of the coefficient in front of d. If you are unsure why it's -5d instead of 5d, please ask.

Divide both sides by -5 (since -5/-5 = 1). REMEMBER, since we are dividing by a negative, we must flip the inequality sign.

Answer

d < 0

If you are ever unsure if you have the correct answer, pick a value for the variable that makes the inequality true, here d=-1 would work, and plug it into the original inequality and see if it holds. Here it does (-12 - (-1) = -11, -12 + 4(-1) = -16, and -11 is greater than -16)

I hope this helps

Anne

Algebra

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