The solution of the system of equations is (-3 , -2)
Step-by-step explanation:
Steps for Using Linear Combinations Method)
- Arrange the equations with like terms in columns
- Analyze the coefficients of x or y
- Add the equations and solve for the remaining variable
- Substitute the value into either equation and solve
∵ 3 x - 8 y = 7 ⇒ (1)
∵ x + 2 y = -7 ⇒ (2)
- Multiply equation (2) by 4 to make the coefficients of y are equal in
magnitude and different in sign
∴ 4 x + 8 y = -28 ⇒ (3)
Add equations (1) and (3)
∵ 3 x - 8 y = 7 ⇒ (1)
∵ 4 x + 8 y = -28 ⇒ (3)
∴ 7 x = -21
- Divide both sides by 7
∴ x = -3
Substitute the value of x in equation (2) to find y
∵ x + 2 y = -7 ⇒ (2)
∵ x = -3
∴ -3 + 2 y = -7
- Add 3 to both sides
∴ 2 y = -4
- Divide both sides by 2
∴ y = -2
The solution of the system of equations is (-3 , -2)
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Answer:
r = 2
Step-by-step explanation:
2(8r + 5) = 24 + 9r
16r + 10 = 24 + 9r
16r - 9r = 24 - 10
7r = 14
r = 2
Answer:
62.4 square centimeters
Step-by-step explanation:
The picture of the question in the attached figure
we know that
The surface area of the triangular pyramid is equal to the area of the triangular base plus the area of its three lateral triangular faces
In this problem the triangles are equilateral, that means, the
surface area is equal to the area of four congruent equilateral triangles
so
![A=4[\frac{1}{2}(b)(h)]](https://tex.z-dn.net/?f=A%3D4%5B%5Cfrac%7B1%7D%7B2%7D%28b%29%28h%29%5D)
we have
substitute
![A=4[\frac{1}{2}(6)(5.2)]=62.4\ cm^2](https://tex.z-dn.net/?f=A%3D4%5B%5Cfrac%7B1%7D%7B2%7D%286%29%285.2%29%5D%3D62.4%5C%20cm%5E2)
Answer:
7 to the second power... because 7 times is 49 and 49-49 is 0... so 7 to the second power
