What type of math is this?

25% of what is 30?
and
solve for a: ab=b=3a-d

Your first problem is a percentage problem. 25% = 0.25

0.25 * 30 = 7.5

your doing "is over of equals percnt over 100. so you set it up

30/x =25/100
cross multiply and solve for x

25x= 3000

dicide by 25 for your answer.

this is stuff you learn in algebra. i am confused with the second equation though

But the answer is 120. I have the answers to those questions. I just need to know topics they are included in so I can study.

correction

ab+b=3a-d

Oops, Alex, I misread your problem. I'm sorry.

25% of what is 30
0.25x = 30
x = 30/0.25
x = 120

The first question involves finding a certain percentage of a number, which is a concept in basic arithmetic. To solve the question "25% of what is 30?", you need to find the number that, when multiplied by 25% (or 0.25), gives the result of 30.

To solve this math problem, you can set up an equation. Let's call the unknown number "x". The equation would be: 0.25 * x = 30.

To find the value of x, you can divide both sides of the equation by 0.25:

x = 30 / 0.25

Calculating this, you will get:

x = 120

Therefore, 25% of 120 is 30.

The second question involves solving for a variable "a" in an equation. It seems there might be a misplacement of the equal sign in the equation provided, as you wrote "ab = b = 3a - d". Assuming it was meant to be "ab + b = 3a - d", I'll explain how to solve it.

To solve for "a", you need to isolate the variable on one side of the equation. Here's how you can do it step-by-step:

Step 1: Simplify the equation by combining like terms on both sides.
ab + b = 3a - d

Step 2: Move all terms with "a" to one side of the equation by subtracting 3a from both sides.
ab + b - 3a = -d

Step 3: Rearrange the equation to isolate "a" on one side.
-3a = ab + b - d

Step 4: Divide both sides of the equation by -3 to solve for "a".
a = (ab + b - d) / -3

This gives you the value of "a" in terms of the other variables and constants in the equation.