18. It is 18 because when you multiply 2x2 plus 4 x2 plus 2 x3 you get 4 plus 8 plus 6 = 18
Answer:
Isolate the variable by dividing each side by factors that don't contain the variable.
4(x−7)=2(x+3)
Simplify both sides of the equation.
4(x−7)=2(x+3)
4x+−28=2x+6
4x−28=2x+6
Subtract 2x from both sides.
4x−28−2x=2x+6−2x
x−28=6
Add 28 to both sides.
2x−28+28=6+28
2x=34
Divide both sides by 2.
2x/2 = 34/2
x = 17
Let , missing value(_)=A
As, it is given that ,

To convert the value of A into Radians,
360°=2 π Radians

So, missing value to the nearest hundredth= 1.26 Radians
5x+6y=18
5x=18-6y
x=(18-6y)/5
Use that in the other equation
18(18-6y)/5 - 15y = 36
64.8-21.6y - 15y = 36
28.8=36.6y
.7868=y
Now put that number in for y on the first equation
5x+6(.78) = 18
5x + 4.68 = 18
5x = 13.32
x = 2.66
and y = .78