5x-8y=1...(1)
3x+6y=-21...(2)
(1)*3:
15x-24y=3...(3)
(2)*5:
15x+30y=-105...(2)
(3)-(2):
15x-24y-(15x+30y)=3-(-105)
15x-24y-15x-30y=108
-54y=108
y=-2
The total cost of the mirror would be $24 because 6 times 4 equals 24.
<h2>
Answer:</h2>
.
<h2>
Step-by-step explanation:</h2>
<h3>1. Write the expression.</h3>

<h3>2. Substitute y for x, and x for y.</h3>

<h3>3. Solve for y.</h3>

<h3>4. Express your result.</h3>
.
The value of k is 400 points.
If the player fails to complete 100 tasks, then they lost 200 points. At the end of the game, they had 200 points.
We can write and solve the following equation to determine where they started.
x - 200 = 200
x = 400
F1 . . . 100% of it = 900N is in the +x direction.
F2 . . . 70.7% of it (cos45°, 530.3N) is in the +x direction,
and 70.7% of it (sin45°, 530.3N) is in the +y direction.
F3 . . . 80% of it (520N) is in the -x direction,
and 60% of it (390N) is in the +y direction.
Total x-component: 900 + 530.3 - 520 = 1,950.3 N
Total y-component: 530.3 + 390 = 920.3 N
Magnitude of the resultant = √ (x² + y²)
= √(1950.3² + 920.3²)
= √4,650,070.09
= 2,156.4 N .
Angle of the resultant, measured counterclockwise
from the +x axis, is
tan⁻¹ (y / x)
= tan⁻¹ (920.3 / 1950.3)
= tan⁻¹ (0.4719)
= about 25.3° .
Caution:
The same fatigue that degrades my ability to READ the question accurately
may also compromise the accuracy of my solutions. Before you use this
answer for anything, check it, check it, check it !