3x - 18 = 42
3x = 42 + 18
3x = 60
x = 60/3
x = 20
Answer:
and 
Step-by-step explanation:
Given that 
and 
, the parametric equations are obtained by algebraic means:
1) Given
2) 
Given
3) 
Associative and modulative properties
4) ![y = 5\cdot \left[(-1)^{-1} \cdot (-1)\right]\cdot x +11](https://tex.z-dn.net/?f=y%20%3D%205%5Ccdot%20%5Cleft%5B%28-1%29%5E%7B-1%7D%20%5Ccdot%20%28-1%29%5Cright%5D%5Ccdot%20x%20%2B11)
Existence of multiplicative inverse/Commutative property
5) ![y = [5\cdot (-1)^{-1}]\cdot [(-1)\cdot x]+11](https://tex.z-dn.net/?f=y%20%3D%20%5B5%5Ccdot%20%28-1%29%5E%7B-1%7D%5D%5Ccdot%20%5B%28-1%29%5Ccdot%20x%5D%2B11)
Associative property
6) 
/ 
7) 
Modulative property
8) ![y = -5\cdot [-x + 2 + (-2)]+11](https://tex.z-dn.net/?f=y%20%3D%20-5%5Ccdot%20%5B-x%20%2B%202%20%2B%20%28-2%29%5D%2B11)
Existence of additive inverse
9) ![y = -5 \cdot [(2-x)+(-2)]+11](https://tex.z-dn.net/?f=y%20%3D%20-5%20%5Ccdot%20%5B%282-x%29%2B%28-2%29%5D%2B11)
Associative and commutative properties
10) 
Distributive property
11) 
12) 
By 1)
13) 
/Result
14) 
Compatibility with addition
15) 
Compatibility with addition
16) ![[t+(-t)]+x= 2 + [x+(-x)]+(-t)](https://tex.z-dn.net/?f=%5Bt%2B%28-t%29%5D%2Bx%3D%202%20%2B%20%5Bx%2B%28-x%29%5D%2B%28-t%29)
Associative property
17) 
Associative property
18) Associative and commutative properties/Definition of subtraction/Result
In consequence, the right answer is and .
Answer:
(x, y) = (77/240, -3/10)
Step-by-step explanation:
It is convenient to write the equations in standard form.
Multiplying the first equation by 21 gives ...
21y = 24x -14
Multiplying the second equation by 8 gives ...
24x +9y = 5
Then the system of equations in standard form is ...
Subtracting the first from the second, we get ...
(24x +9y) -(24x -21y) = (5) -(14)
30y = -9
y = -9/30 = -3/10
Substituting this into the second equation, we have ...
24x +9(-3/10) = 5
24x = 7.7 . . . . . . . add 27/10
x = 7.7/24 = 77/240
The solution is (x, y) = (77/240, -3/10).
