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Harman [31]
2 years ago
10

Which equation combines with the given equation to form a system of equations with the solution x = 3 and y = 9? x + 2y = 21

Mathematics
2 answers:
max2010maxim [7]2 years ago
6 0
Yes. x=3 and y =9 are the solutions.
 Because if you change x=3 and y =9 ,you will have 
3+2* 9 =21
3+18 =21
21 =21 (true)
Gekata [30.6K]2 years ago
4 0

Answer:

x + 2y = 21

Step-by-step explanation:

Even other options have not been given in this question, But we will prove that equation that combines to form a system of equations is x + 2y = 21

For this we will prove this equation true for x = 3 and y = 9

x + 2y = 21

3 + 2×9 = 21

3 + 18 = 21

21 = 21

Therefore, equation x + 2y = 21 combines to form a system of equations.

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In 7.56 mili sec the object will hit the ground
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The line 3y+x=25 is a normal to the curve y=x2-5x+k.find the value of constant k.
ladessa [460]

Answer:

k = 11.

Step-by-step explanation:

y = x^2 - 5x + k

dy/dx = 2x - 5 = the slope of the tangent to the curve

The slope of the normal = -1/(2x - 5)

The line  3y + x =25 is normal to the curve so finding its slope:

3y = 25 - x

y = -1/3 x + 25/3 <------- Slope is -1/3

So at the point of intersection with the curve, if the line is normal to the curve:

-1/3 = -1 / (2x - 5)

2x - 5 = 3  giving x = 4.

Substituting for x in y = x^2 - 5x + k:

When x = 4, y =  (4)^2 - 5*4 + k  

y = 16 - 20 + k

so y = k - 4.

From the equation y = -1/3 x + 25/3,  at x = 4

y = (-1/3)*4 + 25/3 = 21/3 = 7.

So y = k - 4 = 7

k = 7 + 4 = 11.

6 0
2 years ago
A bridge is rated to a capacity of 100 British tons. What is the maximum weight the bridge can support in kilograms? (Round to t
S_A_V [24]

Maximum weight the bridge can support in kilograms is 101696

Step-by-step explanation:

  • Step 1: Given capacity of bridge = 100 British tons. Find how many kilograms are equivalent to 1 British ton.

1 British ton = 2240 pounds

1 pound = 0.454 kg

⇒ 1 British ton = 2240 × 0.454 kg = 1016.96 kg

  • Step 2: Find how many kilograms are in 100 British tons.

⇒ 100 × 1016.96 = 101696

3 0
2 years ago
The true average diameter of ball bearings of a certain type is supposed to be 0.5 in. A one-sample t test will be carried out t
Naily [24]

Answer:

Option C - Do not reject the null hypothesis. There is not sufficient evidence that the true diameter differs from 0.5 in

Step-by-step explanation:

We are given;

n = 15

t-value = 1.66

Significance level;α = 0.05

So, DF = n - 1 = 15 - 1 = 14

From the one-sample t - table attached, we can see that the p - value of 0.06 at a t-value of 1.66 and a DF of 14

Now, since the P-value is 0.06,it is greater than the significance level of 0.05. Thus we do not reject the null hypothesis. We conclude that there is not sufficient evidence that the true diameter differs from 0.5 in.

8 0
1 year ago
Ten turns of a wire are helically wrapped around a cylindrical tube with outside circumference 4 inches and length 9 inches. The
kari74 [83]

Answer:

b) 36 inches

Step-by-step explanation:

Length  of the  wire = Outside circumference of the cylindrical tube * length of the cylinder

= 4 * 9

= 36 inches

Length of the wire will be same to the surface area of the cylinder

Surface area of cylinder = circumference * length

8 0
1 year ago
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