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
15·0.8 + x = 30·0.9 --> x = 15
C. is the correct answer
Answer:
x^3+3x^2+4x+5
Step-by-step explanation:
Ok, so what helps me solve this kind of problem is to circle, underline, or box the like terms(the ones with the same exponent and variable). Be sure to note the sign of each term when combining like terms. take it one step at a time, and work downwards starting with the highest exponent. You have -x^3 and +2x^3, which is x^3. Next, you have +2x^2 and +x^2, which is 3x^2. You should write down each of these as you go, so you should now have x^3+3x^2. Then combine the terms with no exponent but with x, which is 5x and -1x, which is +4x. You should have x^3+3x^2+4x now. Lastly, just combine the numbers 1, -1, and 5, which is 5. This gives you an answer of x^3+3x^2+4x+5.
Based on the information given, it can be deduced that the initial cost will be $187 and the hourly rate is $72 per hour.
From the information given, the initial cost is $187. The cost for 2 hours is $259 and the cost for 3 hours is $331.
Therefore, the rate per hour will be:
= $259 - $187 = $72
The equation will then be:
= 187 + 72h
Lastly, the difference in the costs is $72.
Learn more about equations on:
brainly.com/question/13763238
The answer is b good luck!!!
