Answer:
x = 29
Step-by-step explanation:
Follow the directions: substitute 13 for y in the first equation.
x + 13 = 42
Subtract 13 from both sides of the equation.
x +13 -13 = 42 -13
x = 29
First Let we solve the Original system of equations:
equation (1): 
equation (2): 
Multiplying equation (1) by 7, we get


Subtracting,
implies 
Then
Thus the solution of the original equation is
Now Let we form the new equation:
Equation 2 is kept unchanged:
Equation (2):
Equation 1 is replaced with the sum of equation 1 and a multiple of equation 2:
Equation (1): 
Now solve this two equations: 
Multiply (1) by 7 and (2) by 8,


Subtracting,
implies 
Then x=2.
so the solution for the new system of equation is x=2, y=1.
This Show that the solution to the system of equations 8x − 5y = 11 and 7x − 8y = 6 is the same as the solution to the given system of equations
#8 is D
#9 is C
#10 is D
#11 is B
#12 is A
#13 is A
#14 is A
#15 is D
Answer:
No solution
Step-by-step explanation:
Add x and 2x.
3x+9=3x+11
Move all terms containing x to the left side of the equation.
Subtract 3x from both sides of the equation.
3x+9−3x=11
Combine the opposite terms in
3x+9−3x.
Subtract 3x from 3x.
0+9=11
Add 0 and 9.
9=11
Since 9≠11, there are no solutions.
<h3>Hope it is helpful....</h3>