Answer:
Two straight lines with slopes m and m' are parallel when m = m'
Two straight lines with slopes m and m' are perpendicular when m × m' = - 1.
Step-by-step explanation:
Let us assume that the two non-vertical lines in the slope-intercept form are
y = mx + c ........... (1) and
y = m'x + c' ............ (2)
If those two lines are parallel then we can say the slope of them will be the same i.e. m = m'
Now, if given two straight lines (1) and (2) are perpendicular to each other and neither of them is parallel to the axes, then we can write m × m' = - 1. (Answer)
Answer:
a. True
Step-by-step explanation:
By ∝= 5% we mean that there are about 5 chances in 100 of incorrectly rejecting a true null hypothesis. To put it in another way , we say that we are 95% confident in making the correct decision.
In the given question the null hypothesis is
H0: u ≤ 1 hour and Ha: u > 1 hour
So there is a 5% chance that the erroneous conclusion will be made that students spend on average more than 1 hour per assignment.
The given statement is true.
Answer:

Step-by-step explanation:
difference of a number and 9 means to subtract

twice that means multiply by 2

at least is greater than or equal to

-2x + 5 = -1
subtract 5 from both sides: -2x = -6
divide each side by -2: x = 3
plug in 3: 5(3)
multiply: 15
the value of 5x is 15.
Answer:
Step-by-step explanation:
x²-8x-20
=x²-10x+2x-20
=x(x-10)+2(x-10)
=(x-10)(x+2)
second factor is x+2