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Sloan [31]
2 years ago
6

Solve the following using substitution method

Mathematics
1 answer:
Wewaii [24]2 years ago
6 0

Solution :

2a + 2b = 7    ...1)

4a + 3b = 12   ...2)

In equation, 1)

a = (7 - 2b)/2   ...3)

Putting value of a in equation 2) we get :

4 × (7 - 2b)/2  + 3b = 12

2( 7 - 2b ) + 3b = 12

14 - 4b + 3b = 12

b = 2

Putting value of b in 3) we get :

a = ( 7 - 2×2)/2

a = 3/2 = 1.5

Now,

2x - 3y = 16   ...5)

x + 2y = -6    ...6)

x = -6 - 2y

Putting above value of x in eq 5) , we get :

2( -6 - 2y ) - 3y = 16

-12 - 4y - 3y = 16

7y = -28

y = -4

x = -6 - ( 2× -4 )

x = 2

Hence, this is the required solution.

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A car travels 32 km due north and then 46 km in a direction 40° west of north. Find the direction of the car's resultant vector.
tatuchka [14]

Answer:

Step-by-step explanation:

This requires some serious work before we even begin. First off, we will convert the km to meters:

32 km = .032 m

46 km = .046 m

And then we have to deal with the angle given as 40 degrees west of north. An angle 40 degrees west of north "starts" at the north end of the compass and moves towards the west (towards the left in a counterclockwise manner) 40 degrees. That means that the angle that is made with the negative x axis is a 50 degree angle. BUT the way angles are measured in standard form are from the positive x-axis, therefore:

40 degrees west of north = 50 degrees with the negative x axis = 130 degrees with the positive x axis. 130 is the angle measure we use. Phew! Now we're ready to start. Adding vectors requires us to use the x and y components of vectors in order to add them.

A_x=.032cos90.0 so

A_x=0 (the 90 degrees comes from "due north")

B_x=.046cos130 so

B_x=-.030 and if we add those to get the x component of the resultant vector, C:

C_x=-.030   And onto the y components:

A_y=.032sin90.0 so

A_y=.032

B_y=.046sin130 so

B_y=.035 and if we add those together to get the y component of the resultant vector, C:

C_y=.067  Note that since C_x is negative and C_y is positive, the resultant angle (the direction) will put us into QII.

We find the magnitude of C:

C_{mag}=\sqrt{(-.030)^2+(.067)^2}

We will round this after we take the square root to the thousandths place.

C_{mag}=.073m and now for the angle:

\theta=tan^{-1}(\frac{.067}{-.030}) which gives us an angle measure of -67, but since we are in QII, we add 180 to that to get that, in sum:

The magnitude of the resultant vector is .073 m at 113°

6 0
3 years ago
7 x 2 + 2[7 + 3(5 - 2)] + 2<br> ____________________<br> -4 x 2
svetoff [14.1K]

Answer:-6

Step-by-step explanation:

(7*2+2(7+3(5-2))+2)/(-4*2)

(7*2+2(7+3(3))+2)/((-4)*2)

(7*2+2(7+9)+2)/((-4)*2)

(7*2+14+18+2)/((-4)*2)

(14+14+18+2)/((-8)

48/-8

-6

5 0
3 years ago
Can some one help please
RideAnS [48]
Y=2/3x-2 is the equation of the line
3 0
3 years ago
Beth uses the equation T =
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3 years ago
What is the value of: 1/2^-2x^-3y^5 for x=2 and y=-4
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I am almost 100% sure that this is the correct answer -1/32. 
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