5x+3y=17
3y=-5x+17
y=-5/3y + 17/3
Graph if it asks.
Answer:
A) -4x + 9y = 9
B) x -3y = -6
We multiply B) by 3
B) 3x -9y = -18 Then add it to A)
A) -4x + 9y = 9
-x = -9
x = 9
9 -3y = -6
3y = 15
y = 5
Step-by-step explanation:
The answer is x = 10, y = 10.
Step 1: rearrange the second equation for y.
Step 2: substitute y from the second equation into the first equation.
Step 3. Calculate y.
Step 1.
<span>The second equation is: 6x + 3y = 90
Divide both sides of the equation by 3:
(6x + 3y)/3 = 90/3
6x/3 + 3y/3 = 30
2x + y = 30
Rearrange the equation:
y = 30 - 2x
Step 2.
</span>Substitute y from the second equation (y = 30 - 2x) into the first equation:
<span>15x + 9y = 240
15x + 9(30 - 2x) = 240
15x + 270 - 18x = 240
15x - 18x = 240 - 270
-3x = -30
x = -30/-3
x = 10
Step 3.
Since </span>y = 30 - 2x and x = 10, then:
y = 30 - 2 * 10
y = 30 - 20
y = 10
Let α represent the acute angle between the horizontal and the straight line from the plane to the station. If the 4-mile measure is the straight-line distance from the plane to the station, then
sin(α) = 3/4
and
cos(α) = √(1 - (3/4)²) = (√7)/4
The distance from the station to the plane is increasing at a rate that is the plane's speed multiplied by the cosine of the angle α. Hence the plane–station distance is increasing at the rate of
(440 mph)×(√7)/4 ≈ 291 mph
