Answer:
3)5x-4y=-3
6x+4y=14
Step-by-step explanation:
The system of equations is given
5x-4y=-3
3x+2y=7
Multiplying both sides of the lower equation by 2, we get
6x + 4y = 14
That means your answer 3)
Its false because it can't repeat in a set.
Answer:
The height of the pole is 167 m
Step-by-step explanation:
The given parameters are;
Increase in the length of the shadow = 90 m
Initial angle of elevation of the Sun = 58°
Final angle of elevation of the Sun = 36°
We have a triangle formed by the change in the length of the shadow and the rays from the two angle of elevation to the top of the pole giving an angle 22° opposite to the increase in the length of the shadow
We have by sin rule;
90/(sin (22°) = (Initial ray from the top of the pole to the end of the shadow's length)/(sin(122°)
Let the initial ray from the top of the pole to the end of the shadow's length = l₁
90/(sin (22°) = l₁/(sin(122°)
l₁ = 90/(sin (22°) ×(sin(122°) = 283.3 m
Therefore;
The height of the pole = 283.3 m × sin(36°) = 166.52 m
The height of the pole= 167 m to three significant figures.
Answer:
13.20 min
Step-by-step explanation:
Rate of the reaction is a measure of the rate of decomposition of the compound.
Rate (R) = Concentration (C) ÷ time (t)
C1/t1 = C2/t2
C1 = 52.3% = 0.523
t1 = 8.6 min
C2 = 80.3% = 0.803
t2 = C2t1/C1 = 0.803×8.6/0.523 = 13.20 min (to 2 decimal places)