Answer:
1/2
Step-by-step explanation:
We are given the expression 3b²-c, and we want to evaluate it if b is 1/2 and c is 1/4.
Because b and c are given values, we can substitute them into the expression as so:
Replace b with 1/2 in the expression.
3(1/2)²-c
Now replace c with 1/4 in the expression.
3(1/2)²-1/4
Now to solve this, we need to use the order of operations, which is usually known as PEMDAS (parentheses, exponents, multiplication, division, addition, subtraction) in the United States, although other countries have different abbreviations.
Regardless, the order of operations tells us that we should start with what is inside parentheses (i.e. if we need to do anything, like multiplying or dividing any numbers that are inside parentheses).
In this case, we don't have anything. So, we should go next to exponents, and we do have an exponent here (1/2 is raised to the second power).
So let's evaluate that.
Raise 1/2 to the second power (multiply it by itself).
1/2 * 1/2 = 1/4
We can substitute (1/2)² with 1/4:
3(1/4) - 1/4
Next, we should take care of any multiplication / division, making sure that we should work left to right
There is one multiplication thing to do: the 3(1/4), which will be 3/4
Replace 3(1/4) with 3/4.
3/4 - 1/4
Now, we can subtract 1/4 from 3/4, as the final two things in PEMDAS are addition and subtraction (A and S). Note that even though while addition is written first, we should always be working left to right, so for example if we had 3 - 4 + 6, we should do 3 - 4 first, THEN add 6 to the result of that. The same is true for multiplication and division.
3/4 - 1/4 = 2/4 = <u>1/2 </u>
