Answer:
x = -3
Step-by-step explanation:
15 - 2x = -7x
add 2x
15 = -5x
divide by -5
-3 = x
210 - ( 30 * x )
**I assume the question asks for total minutes.
3x - y = 9
y = -2x + 11
3x - (-2x + 11) = 9
3x + 2x - 11 = 9
3x + 2x = 9 + 11
5x = 20
x = 20/5
x = 4
y = -2x + 11
y = -2(4) + 11
y = -8 + 11
y = 3
solution (where the lines intersect) is (4,3)
it will be 8.25 hope this helped
I:2x – y + z = 7
II:x + 2y – 5z = -1
III:x – y = 6
you can first use III and substitute x or y to eliminate it in I and II (in this case x):
III: x=6+y
-> substitute x in I and II:
I': 2*(6+y)-y+z=7
12+2y-y+z=7
y+z=-5
II':(6+y)+2y-5z=-1
3y+6-5z=-1
3y-5z=-7
then you can subtract II' from 3*I' to eliminate y:
3*I'=3y+3z=-15
3*I'-II':
3y+3z-(3y-5z)=-15-(-7)
8z=-8
z=-1
insert z in II' to calculate y:
3y-5z=-7
3y+5=-7
3y=-12
y=-4
insert y into III to calculate x:
x-(-4)=6
x+4=6
x=2
so the solution is
x=2
y=-4
z=-1
