by the use of elimination method
make all coefficients of subject to be eliminated similar..by multiplying the coefficients with one another
for eqn(i)
5(-10y+9x=-9)
-50y+45x=-45
for eqn(ii)
9(10y+5x=-5)
90y+45x=-45
-50y+45x=-45
90y+45x=-45
...subtract each set from the other...
we get
-140y+0=0
y=0
from eqn(i)
10y+5x=-5
0+5x=-5
x= -1
The time needed at 2 meters per second for both rounds would be 100/2 s or 50 seconds. For the first lane he already used 50/1.5 -> 33.33 seconds, so he would need to cover the other 50 meters in exactly 16.67. 50m divided by the 16.67 seconds he has left means he has to swim at a speed of 3 meters per second.
0.15x + x <(or equal to) 50
Where x is the meal's cost (no tip included)
50 - 15% = 42.5.
x >(or equal to) 42.50.
(nothing is copied content, I copy pasted a number into the right position, feel free to check it mods)
Answer:..
Step-by-step explanation:
