1)
x^2 - 49 = 0
factor
(x+7)(x-7) = 0
x+7 = 0; x = -7
x -7 = 0; x = 7
2)x^2 - 18x + 81 = 0
factor
(x- 9)(x - 9) = 0
x - 9=0; x = 9
3)
x^2 + 3x = 40
x^2+3x - 40 = 0
factor
(x + 8)(x - 5) = 0
x+8 = 0; x = -8
x -5 = 0; x = 5
4)
3x^2 - 75 = 0
3(x^2 - 25) = 0
3(x+5)(x-5) = 0
x + 5 = 0; x = -5
x - 5 = 0; x = 5
5)
2x^2 - 15 = 7x
2x^2 - 7x - 15 = 0
(2x + 3)(x - 5) = 0
2x+3 = 0; x = -3/2
x - 5= 0; x = 5
6)
4x^2 + 16x - 48 = 0
4(x^2 + 4x - 12) = 0
4(x + 6)(x - 2) = 0
x + 6 = 0; x = -6
x - 2 = 0 ; x = 2
Answer:
12ft
Step-by-step explanation:
Behold, my crudely drawn diagram!!!
Edit: The red side is the hypotenuse/escalator length, the green side is adjacent to the angle/the escalator height, and the blue bits refer to the angle. Also it's supposed to be a right triangle but I forgot the little box we typically put in the corner to indicate the 90° angle.
Using some geometric knowledge of right triangles, we know that the Cosine of an angle is equal to the length of the adjacent side divided by the lenght of the hypotenuse. So:
Cos(39.81°) = h ÷ 15.5ft
*Here I've called the top of the escalator's height "h"*
By solving for h and plugging it into a calculator I get:
h = Cos(39.81°)•(15.5) = 11.906...
But they want it rounded to the nearest foot, so your answer is 12ft.
Answer: x=no solution
Step-by-step explanation:
Answer: 5.18 pound per square inch
Step-by-step explanation:
According to pressure law, the pressure of a gas is directly proportional to the temperature
P1/T1 = P2/T2
where P1 is the initial pressure = 6 pounds
T1 is the initial to temperatures = 440°F
P2 is the final pressure = Z
T2 is the final temperature = 380°F
Thus, let final pressure be Z
P1/T1 = P2/T2
6/440 = Z/380
0.0136 = Z/380
Make Z the subject formula
Z = 380 x 0.0136
Z = 5.18 pound per square inch
Thus, the final pressure at 380°F is 5.18 psi (pound per square inch)