Answer:
(2, - 4 )
Step-by-step explanation:
Given the 2 equations
x + 2y = - 6 → (1)
3x + y = 2 → (2)
Multiplying (2) by - 2 and adding to (1) will eliminate the term in y
- 6x - 2y = - 4 → (3)
Add (1) and (3) term by term to eliminate y
- 5x = - 10 ( divide both sides by - 5 )
x = 2
Substitute x = 2 into either of the 2 equations and solve for y
Substituting into (1)
2 + 2y = - 6 ( subtract 2 from both sides )
2y = - 8 ( divide both sides by 2 )
y = - 4
Solution is (2, - 4 )
is the only acute angle whose sin = 1/2. Therefore, cos (
) =
If his water to cement ratio is 20 to 30, this means that if he uses 20 liters of water, he'd use 30 liters of cement.
The total mixture would then be 20+30=50 liters.
and the water would be 20/50=0.4 or 40% of the total mixture.
Hoi!
If the two fractions have a common denominator, then yes, you do. Only add the numerators. :)
