All categories

3 years ago

Evaluate the expression for x = 3 and y = 5. 12x−3y

Mathematics

2 answers:

Advocard [28]3 years ago

6 0

12x-3y=21
4x-y=7
I hope this helps

Eddi Din [679]3 years ago

5 0

The first one is 21 12 times 3 is 36 minus 3 times 5 is 15 36 minus 15 is 21
Next one 4 times 3 is 12 minus 5 is 7
12x-3y=21
4x-y=7

You might be interested in

a table that originally cost $196 is on sale for $160.00. What is the percent of decrease, rounded to the nearest tenth?

AfilCa [17]

Hmmm.. I solved it and got 82%. I may be wrong, but try it out.

8 0

3 years ago

Read 2 more answers

an online movie stream plan charges an annual fee of $45 plus $2.50 per movie watched.Another plan has no annual fee but charges

Anastasy [175]

Ah, great question. Let me help you on this one.

We need to balance both equations for this to work out. This is needed because question asks us for an x variable that will make both equations equal to each other.

Let's write it out so it's easier for us to understand.

Let's not forget to multiply both sides by 100.

$4500+(250x)=375x$

Let's start by subtracting 45 from both sides.

$4500+(250x)-4500=375x-4500$

Let's simplify it.

$250x=375x-4500$

Now, we need to subtract 375 from both sides.

$250x - 375=375x-4500+(-375)$

Simplify it once again.

$-125x=-4500$

Divide both sides by -125

$x=36$

This plan will be the same cost after 36 movies.

7 0

3 years ago

Please help me understand how to solve equations like these, I don’t understand them:

algol [13]

Answer:

subtract the unwanted b term
divide by the coefficient of b
b = 60

Step-by-step explanation:

The numbers 4/5 and 9/10 are fractions. They multiply the variable 'b' in each case.

How to solve an equation like this

An example of an equation like this without fractions is ...

6 + 3b = 8b

You solve this sort of equation by rearranging the equation so the terms having 'b' in them are all on one side of the equal sign. You want all of the terms not containing 'b' to be on the other side of the equal sign.

Here, the terms are mixed on the left, but the right has only a 'b' term. So, if we can remove the 'b' term from the left side, we will have reached the goal

In the example equation, we do that by adding -3b to both sides of the equation.

6 +3b -3b = 8b -3b

Simplifying, we have ...

6 = 5b

Now, we divide by the coefficient of 'b', which is 5. We divide both sides of the equation by that:

6/5 = (5b)/5

6/5 = b . . . . after simplifying

_____

How to solve this equation

The given equation is solved exactly the same way. We add the opposite of the 'b' term that we don't want (which is 4/5b):

6 + 4/5b -4/5b = 9/10b -4/5b

Simplifying, this is ...

6 = (9/10 -4/5)b = (9/10 -8/10)b

6 = 1/10b

We can make the coefficient of 'b' be 1 by multiplying it by 10. We have to do that to both sides of the equation:

(10)(6) = (10)(1/10)b

60 = b . . . . . the solution

_____

Comment on equations in general

The one absolute rule in Algebra is that the equal sign must remain valid. You keep that commandment by observing the properties of equality. Essentially, you can do anything you like to one side of an equation, as long as you do exactly the same thing to the other side.

Here, when we say "subtract 4/5b", the way we keep this commandment is that we do it to both sides of the equation. The same is true for "multiply by 10". This is emphasized by the bold highlighting in the solution shown above.

Comment on arithmetic

In solving this equation, we did the arithmetic using the given fractions. Often, for an equation like this, you will be told the first step is to "eliminate fractions". You can do that here by multiplying the equation by 10:

10(6 +4/5b) = 10(9/10b)

60 +8b = 9b

Now, the unwanted term is 8b, so subtracting that (from both sides) gives ...

60 = b

This is essentially a "2-step" equation, either way you do it.

It is helpful if you are comfortable doing arithmetic with fractions, mixed numbers, decimals, percentages, and numbers in scientific notation, as well as integers.

4 0

3 years ago

Write a rational number in fraction form that is equivalent to -1.\overline{5}

lorasvet [3.4K]

Answer:

$\dfrac{-14}{9}$ .