Answer:
28-4x
Step-by-step explanation:
Step 1: Open most inner bracket and simplify
=18-2(x+x-5)
=18-2(2x-5)
Step 2: Expand brackets by multiplying 2 in and simplify
=18-2(2x)-2(-5)
=18-4x+10
=28-4x
Therefore the answer is 28-4x
7, -13 should be 2
-2, -10 should be -6
Answer:
1) x- y = 8
x + y = 12
eliminate one variable by adding the equations
2x = 20
divided by 2 on both sides
x = 10
substitute the value of x in the equation 1
10 - y = 8
-y = 8- 10
y =2
[x , y]
[10 , 2]
2) 2x - y = 4
3x + y = 6
eliminate one variable by adding the equations
5x = 10
x = 2
substitute the value of x in the equation
2(2) - y = 4
4 - y = 4
y = 0
[x ; y]
[2; 0]
3) x + 2y = 10
x + 4y = 14
multiply equation 1 by - 1
-x -2y = -10
x + 4y = 14
eliminate one variable by adding the equations
2 y = 4
y = 2
substitute the value of y in the equation 1
x + 2(2) = 10
x + 4 = 10
x = 6
[x ; y]
[6 ; 2]
4 ) 3x + y = 9
y = 3x + 6
simplify the expression
3x + y = 9
- 3x + y = 6
eliminate one variable by adding the equations
2y = 15
y = 15/2
substitute the value of y in equation 1
3x + 15/ 2 = 9
3x = 3/2
x = 1/2
[x ; y]
[1/2 ; 15/ 2]
5) 4x + 5y = 15
6x - 5y = 18
eliminate one variable by adding the equations
10 x = 33
× = 33/10
substitute the value of x in equation I
4 (33/10) + 5y = 15
66/5 + 5y =15
5y = 9/5
y = 9/25
[x ; y]
[33/10 ; 9/25]
6) 5x = 7y
x + 7y = 21
in equation I move the variable to the left
5x - 7y = 0
x + 7 y = 21
eliminate one variable by adding the equations
6x = 21
x = 7/2
substitute the value of x in the equation
5(7/2) = 7y
35/2 = 7y
5/2 = y
[x ; y ]
[7/2 ; 5/2 ]
Answer/Step-by-step explanation:
Part A:
Evidence 1: the line passes through the point of origin, (0, 0)
Evidence 2: it has a unit rate or constant of proportionality, k = y/x = 5/3
Part B:
When extended, if the ray passes through the point, (18, 30), then y/x of this point, should give us the same unit rate (k) of 5/3 of the graph.
Thus:
y/x = 30/18
Simplify
= 5/3
Thus, it has the same unit rate of the graph, therefore, the ray passes through the point (18, 30).
2x+y=8
this equation is perpendicular to 2x-y=5 and passes through the point (6,-4)