Answer:
x = 10/3
, y = 0
Step-by-step explanation:
Solve the following system:
{4.5 x - 2 y = 15
3 x - y = 10
In the first equation, look to solve for x:
{4.5 x - 2 y = 15
3 x - y = 10
4.5 x - 2 y = (9 x)/2 - 2 y:
(9 x)/2 - 2 y = 15
Add 2 y to both sides:
{(9 x)/2 = 2 y + 15
3 x - y = 10
Multiply both sides by 2/9:
{x = (4 y)/9 + 10/3
3 x - y = 10
Substitute x = (4 y)/9 + 10/3 into the second equation:
{x = (4 y)/9 + 10/3
3 ((4 y)/9 + 10/3) - y = 10
3 ((4 y)/9 + 10/3) - y = ((4 y)/3 + 10) - y = y/3 + 10:
{x = (4 y)/9 + 10/3
y/3 + 10 = 10
In the second equation, look to solve for y:
{x = (4 y)/9 + 10/3
y/3 + 10 = 10
Subtract 10 from both sides:
{x = (4 y)/9 + 10/3
y/3 = 0
Multiply both sides by 3:
{x = (4 y)/9 + 10/3
y = 0
Substitute y = 0 into the first equation:
Answer: {x = 10/3
, y = 0
Answer:
x = π/4 and 5π/4
Step-by-step explanation:
Given the expression;
2cos²x - 1 = 0
2cos²x = 0+1
2cos²x = 1
cos²x = 1/2
cos x = ±√1/2
cos x = ±0.7071
x = arccos(±0.7071)
x = ±45 degrees
Convert to radians
Sence 180° = π rad
45° = x
x = 45π/180
x = π/4
If x = -45°
Since cos is negative in the 3rd quadrant
x = 180 + 45
x = 225°
x = 225π/180
x = 45π/36
x = 5π/4
I have no idea, someone help
I think the answer is 18.7
Idk about number 4 but I think the other ones are correct
