4. .5 per ounce so 3.5 for 7 ounces
5. 7.5 degree every hour so 22.5 for 3 hours
6. 61 miles per hour so 305 for 5 hours
your answer is C. substraction
X - y = 5....x = 5 + y
6x = 8y
6(5 + y) = 8y
30 + 6y = 8y
30 = 8y - 6y
30 = 2y
15 = y
x - y = 5
x - 15 = 5
x = 15 + 5
x = 20
ur 2 numbers are : 20 and 15
This will be easier to write, and a lot easier to read, if we temporarily
use another symbol ... say, 'Q' ... to represent ' sin(2x) ' .
Here we go:
Original equation: Q² - 0.5 Q = 0
Factor the left side: Q (Q - 0.5) = 0
This equation is true if either factor is zero:
-- If Q=0, then sin(2x) = 0
2x = 0°, 180°, 360°
x = 0°, 90°, 180°
-- If (Q-0.5) = 0, then Q = 0.5
sin(2x) = 0.5
2x = 30°, 150°
x = 15°, 75°
The whole collection of solutions
between 0° and 360° :
x = 0°, 15°, 75°, 90°, 180° .
