Answer:
PL and LM
Step-by-step explanation:
The definition of perpendicular is two lines that create a 90 degree angle. There are a lot of those in a rectangular prism. One of them is PL and LM, because they intersect to create a right angle.
Answer:
(-18,9)
Step-by-step explanation (work shown in picture attached):
1) The first step in solving by substitution is to isolate the y-term in one of the equations if it is not already isolated. Isolate y in the first equation by dividing both sides by -2. This leaves us with the equation
2) Now, substitute
for the y in the second equation. Simplify and isolate x. (You can multiply everything by -2 to get rid of the fraction.) This leaves us with x = -18.
3) We've found the x-value of the solution, -18. Now, substitute -18 for x back into one of the original equations (I chose the first one because it was simple) and isolate y. This gives us y = 9. Thus, in point form, the answer is (-18,9).
Answer: x = 7 or x = -8
x² + x - 56 = 0
⇔ x² + 8x - 7x - 56 = 0
⇔ x(x + 8) - 7(x + 8) = 0
⇔ (x - 7)(x + 8) = 0
⇔ x - 7 = 0
or x + 8 = 0
⇔ x = 7 or x = -8
Step-by-step explanation: