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Sati [7]
3 years ago
7

What is the value of the expression 2x^2 + 3xy - 4y^2 when x = 2 and y = -4?

Mathematics
1 answer:
Vera_Pavlovna [14]3 years ago
5 0

Answer:

-80

Step-by-step explanation:

2x^2 + 3xy - 4y^2  

x = 2 | y = - 4

2(2)^2 + 3(2)(-4) - 4(-4)^2

2 * 4 + 3(2)(-4) - 4 * 16

8 - 24 - 64

-80

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Solve the system of equations by graphing. Check your solution.<br><br> 5x+y=14<br> 2x-y=7
Fudgin [204]
ANSWER

(3,-1)

EXPLANATION

The given system of equations is :

5x+y=14

2x-y=7

For the first equation when x=0,

5(0)+y=14

y=14

The y-intercept is (0,14).

When y=0, 5x+0=14

x = \frac{14}{5} = 2 .8

The x-intercept is (2.8,0).

We plot the intercepts and draw a straight line through them to obtain the graph of 5x+y=14 as shown in the attachment.

We repeat the same process for the second equation 2x-y=7.

The intercepts are (0,-7) and (3.5,0)

The solution to the system is the point of intersection of the two straight lines.

The two straight lines intersected at

(3,-1)

Hence x=2, y=-1

6 0
4 years ago
.0194 also equals what, 4,200, 11.7, 1.17, or 0.117
schepotkina [342]

I think it equals 1.17.


7 0
4 years ago
What is 1/4 of 100? You need to explain your answer in the simplest form
slega [8]

Answer:

25

Step-by-step explanation:

<u>1/4 * 100 gives us a quarter of 100 which is 25.  Just like the quarter in the American currency, it is 1/4 of 100 and that is 25 cents.</u>

<u />

Answer:  25

5 0
4 years ago
2 is on the line 4x - 5y = -7 find the other half of the coordinate
natali 33 [55]
4x - 5y = -7

When x = 2, 
4(2) - 5y = -7
8 - 5y = -7
5y = 15
y = 5

Answer: The other half of the coordinate is 5. 

4 0
3 years ago
What is the slope of the line?<br> a. –2<br> b. –1/2<br> c. 1/2<br> d. 2
mojhsa [17]

Hey!


The formula for slope is: \frac {y_2-y_1} {x_2-x_1} or: \frac{change\ in\ x}{change\ in\ y}


y₂ = 2

y₁ = 3


x₂ = 4

x₁ = 2


That gives you:


\frac{2-3}{4-2} = \frac{-1}{2}


That means your answer is B


\framebox{Answer = B.}


6 0
3 years ago
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