Plz help me it is hard

Solve the system by substitution. x= 2y + 7 3x – 2y = 3 The solution is?

seropon [69]

Hi there! Your answer is x = -2, y = -9/2

In coordinate point, we can write (-2,-9/2)

Please see the explanation below for a clear understand about the problem.

Any questions about the answer, feel free to ask in comment! :)

Step-by-step explanation:

Goal

Solve the system of equations by substitution method.

Given

System of Equations

$\begin{cases} x=2y+7 \Longrightarrow (1)\\ 3x-2y=3 \Longrightarrow (2) \end{cases}$

Step 1

Since our x-term is the subject in the first equation, we can simply substitute x = 2y+7 in the second equation.

Substitute x = 2y+7 in the second equation.

$3x-2y=3\\3(2y+7)-2y=3$

We do this so we can solve for the y-term without any problems. (We need to get rid of a variable if there are more than one variable.)

Then we distribute/expand 3 in the expression.

$6y+21-2y=3\\4y+21=3$

Step 2

Solve the equation for y-term

To solve the equation, we have to isolate the term that we want. For this scenario, we want to know the value of y-term. Therefore, we isolate y-term.

$4y=3-21\\4y=-18\\y=-\frac{18}{4} \\y=-\frac{9}{2}$

Finally! we know the value of y which is -9/2. But we are not done yet!

Step 3

Substitute the y-value in any given equations.

After we solve the equation, we have to substitute the value in any given equations. No need to substitute the value in both equations! Choose an equation to substitute the value in.

For this, I will be choosing an equation with less coefficients which is the first equation.

$x=2y+7$

Substitute y = -9/2 in the equation.

$x=2(-\frac{9}{2})+7\\x=-9+7\\x=-2$

We should get x = -2 as the answer. This is our last step for finding an answer. The next few steps are going to be how to check the answer for system of equations. Note that next few steps are optional. If you are not certain that the answer is wrong or right, it is highly advised to check the answer before jumping to a conclusion!

Optional Steps - Answer Check

To check the answer, we can simply substitute both x-value and y-value in any given equations. You can either choose only a single equation to substitute in ONLY if you are certain/sure that the answer is likely correct. Substituting in both equations are recommended for beginners.

Step 3

Substitute x = -2 and y = -9/2 in the system of equations.

Step 3.1

Substitute in x = 2y+7

$x=2y+7$

From x = -2 and y = -9/2

$-2=2(-\frac{9}{2} )+7$

Cancel 2 out.

$-2=-9+7\\-2=-2$

As you can see, both sides are equal. That means the equation is true for x = -2 and y = -9/2.

Step 3.2

Substitute in 3x-2y = 3

$3x-2y=3$

Substitute x = -2 and y = -9/2 in the equation.

$3(-2)-2(-\frac{9}{2})=3\\-6+\frac{18}{2}=3\\-6+9=3\\3=3$

Since both equations are true for x = -2 and y = -9/4. We can conclude that:

$\huge\sf{x = -2 \ and \ y = -\frac{9}{2} \ are \ the \ solutions \ to \ the \ system \ of \ equations.}$

Hence, the answer is x = -2 and y = -9/2.

5 0

3 years ago

What is the result if you divide 18r4 s5 t6 / -3 r2 st3 ?

coldgirl [10]

The answer for the given above is letter "a, -6r2s4t3". This is obtained by dividing 18 by -3 and subtracting the exponent below with that from above of the same variable. For r, subtract 2 from 4 to get 2. For s, subtract 1 from 5 to get 4 and lastly for t, subtract 3 from 6 to get 3.

5 0

3 years ago

Read 2 more answers

The perimeter of a rectangular field is 372 yards. If the width of the field is 87 yards, what is its length?__yards

worty [1.4K]

ANSWER

The length of the rectangular field is 99 yards

EXPLANATION

Given information

The perimeter of a rectangle field is 372 yards

The width of the field is 87 yards

To find the length of the rectangular field, follow the steps below

Step 1: Write the formula for finding the perimeter of a rectangular field

$\begin{gathered} \text{ The perimeter of a rectangular field = 2\lparen l + w\rparen} \\ \text{ where l =length, and w = width} \end{gathered}$

Step 2: Substitute the given data into the formula in step 1

$\begin{gathered} \text{ Perimeter = 2 \lparen l + w\rparen} \\ \text{ Perimeter = 372 yards} \\ \text{ width = 87 yards} \\ \text{ 372 = 2\lparen l + 87\rparen} \\ \text{ Divide both sides by 2} \\ \text{ }\frac{372}{2}\text{ = }\frac{2}{2}(l\text{ + 87\rparen} \\ 186\text{ = l + 87} \\ \text{ subtract 87 from each sides of the equation} \\ \text{ 186 - 87 = l + 87 - 87} \\ \text{ 99 = l} \\ l\text{ = 99 yards} \end{gathered}$

Hence, the length of the rectangular field is 99 yards

7 0

1 year ago

B. If some amount of water contains 1400 oxygen atoms, how many hydrogen atoms does it contain?

Genrish500 [490]

Answer:

B: 2800 hydrogen atoms

C: 6760 hydrogen atoms

D: y=amount of oxygen atoms*2

Step-by-step explanation:

B: We know the formula for water is H2O. SO that means that there is 2 hydrogen atoms and 1 oxygen atom. So there is 2 times the amount of hydrogen atoms so we can do 1400*2=2800, So there is 2800 hydrogen atoms in the water.

C: Same thing as B. 3380*2=6760

D: y=amount of oxygen atoms*2. Because there is one oxygen atom and two hydrogen atoms so 1*2=2.

5 0

3 years ago

Solve for x in the equation x^2 + 4x - 4 = 8

erik [133]

Subtracting 8 from both sides of the equation gives

x^2 + 4x - 12 = 0

(x + 6)(x - 2)= 0

x = -6, 2 answer

3 0

3 years ago

Read 2 more answers