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iren [92.7K]
4 years ago
11

Solve the system using substitution.

Mathematics
1 answer:
Maru [420]4 years ago
5 0

Answer:

Given: The following system:

4x + y − 2z=18          ......[1]

2x-3y+3z = 21          ......[2]

x-3y=6                      ......[3]

we can write equation [3] as;

3y = x-6                     ......[4]

Multiply by 3 in equation [1] to both sides of an equation we get,

3 \cdot(4x+y-2z)= 3\cdot 18 or

12x+3y-6z=54              ......[5]

Substituting the equation [4] in [2] and [5] we get;

2x-(x-6)+3z=21 or

2x-x+6+3z=21

Simplify:

x+3z=15            .....[6]                       [combine like terms]

12x+x-6-6z =54

Simplify:

13x-6z=60         ......[7]        [Combine like terms]

On Solving equation [6] and [7] simultaneously,

x+3z=15

13x-6z=60

we get the value of x

i.e, x=6

Substitute the value of x in equation x+3z=15  we get

6+3z=15 or

3z=9

Simplify:

z=3

Also, substitute the value of x=6 in equation [3] we get the value of y;

x-3y=6

6-3y=6 or

-3y = 0

Simplify:

y = 0

Therefore, the solution to the system of three linear equation is, (6, 0 , 3)


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Find the x- and y-intercepts of the following line: 4x − 3y = 12
Slav-nsk [51]

Answer:

x-intercept: (3,0)

y-intercept: (0,-4)

Step-by-step explanation:

To find the x and y-intercepts, we first need to understand what they are. X and y-intercepts are points on the line that passes through the x-axis and y-axis. When a point is an x-intercept, it passes through the x-axis. This means the x-coordinate is an integer, while the y-coordinate is always 0. This can be denoted by (x,0). When a point is a y-intercept, it passes through the y-axis. This means the y-coordinate is an integer, while the x-coordinate is always 0. This can be denoted by (0,y).

Now that we know what x and y-intercepts are, we can plug in x=0 and y=0 to find the intercepts.

x-intercept

4x-3y=12            [plug in y=0]

4x-3(0)=12          [multiply]

4x-0=12              [add both sides by 0]

4x=12                 [divide both sides by 4]

x=3

---------------------------------------------------------------------------------------------------------

y-intercept

4x-3y=12            [plug in x=0]

4(0)-3y=12         [multiply]

0-3y=12             [subtract both sides by 0]

-3y=12               [divide both sides by -3]

y=-4

Therefore, the x-intercept is (3,0) and y-intercept is (0,-4).

3 0
3 years ago
I need helppppp ughhhhhhh
GarryVolchara [31]
Wrong person I pay someone to do my math for me :)
7 0
3 years ago
What is 12-9×3×4+3 in three different ways
Maurinko [17]
1. 12-9×3×4+3=-93
2.3+4×3×9-12=99
3. 12-9+3×9×3×4=327
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3 years ago
A researcher wants to see if birds that build larger nests lay larger eggs. He selects two random samples of nests: one of small
True [87]

Answer:

95% confidence interval for the difference between the average mass of eggs in small and large nest is between a lower limit of 0.81 and an upper limit of 2.39.

Step-by-step explanation:

Confidence interval is given by mean +/- margin of error (E)

Eggs from small nest

Sample size (n1) = 60

Mean = 37.2

Sample variance = 24.7

Eggs from large nest

Sample size (n2) = 159

Mean = 35.6

Sample variance = 39

Pooled variance = [(60-1)24.7 + (159-1)39] ÷ (60+159-2) = 7619.3 ÷ 217 = 35.11

Standard deviation = sqrt(pooled variance) = sqrt(35.11) = 5.93

Difference in mean = 37.2 - 35.6 = 1.6

Degree of freedom = n1+n2 - 2 = 60+159-2 = 217

Confidence level = 95%

Critical value (t) corresponding to 217 degrees of freedom and 95% confidence level is 1.97132

E = t×sd/√(n1+n2) = 1.97132×5.93/√219 = 0.79

Lower limit = mean - E = 1.6 - 0.79 = 0.81

Upper limit = mean + E = 1.6 + 0.79 = 2.39

95% confidence interval for the difference in average mass is (0.81, 2.39)

3 0
3 years ago
Mrs. Cervantes wants to paint her windmill. It has six sides, each of which is 3.5 feet wide by 11 feet tall. How many square fe
wolverine [178]

Answer:

231 ft²

Step-by-step explanation:

Given that :

Dimension of each side = 3.5 feets by 11 feets

Area of each side :

Length * width = (3.5 * 11) feets = 38.5 ft²

Number of sides = 6

Hence, number of square feets to paint :

Number of sides * area of each side :

6 * 38.5 ft²

= 231 ft²

7 0
3 years ago
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