No false.
Remember the solution(s) to a system of equations is where the graphs all intersect if at all.
For the case of say a system of 2 lines, you can see the different possible outcomes..
-- If the two lines intersect at some point (x,y), that is one unique solution
-- If the two lines are parallel to each other, you see there are no intersection points and therefore this system of two parallel lines has no solutuion.
-- If the two lines overlap, really the same line written as a multiple of the other line, then you see they intersect at all points along the line, here there are infinite solutions.
Answer:
68.26% of the parts will have lengths between 3.8 in. and 4.2 in.
Step-by-step explanation:
The lengths of a lawn mower part are approximately normally distributed

Standard deviation =
We are supposed to find What percentage of the parts will have lengths between 3.8 in. and 4.2 in . i.e. P(3.8<x<4.2)
Formula : 
At x = 3.8

Z=-1
Refer the z table for p value
p value =0.1587
At x =4.2

Z=1
Refer the z table for p value
p value =0.8413
P(3.8<x<4.2)=P(x<4.2)-P(x<3.8)=0.8413-0.1587=0.6826
So, 68.26% of the parts will have lengths between 3.8 in. and 4.2 in.
Probably a plane unless there's more to the question
Answer:
b, c, d and f since they have a sign of greater> or less to> or greater and less to
Multiply all terms by 15
3x+3x= 10x+30
Combine like terms
6x=10x+30
Subtract 10x from both sides
-4x=30
Divide both sides by -4
x= -7.5
Final answer: -7.5