Answer:
The method of solving "by substitution" works by solving one of the equations (you choose which one) for one of the variables (you choose which one), and then plugging this back into the other equation, "substituting" for the chosen variable and solving for the other. Then you back-solve for the first variable.
Step-by-step explanation:
Solve the following system by substitution.
2x – 3y = –2
4x + y = 24
The idea here is to solve one of the equations for one of the variables, and plug this into the other equation. It does not matter which equation or which variable you pick. There is no right or wrong choice; the answer will be the same, regardless. But — some choices may be better than others.
For instance, in this case, can you see that it would probably be simplest to solve the second equation for "y =", since there is already a y floating around loose in the middle there? I could solve the first equation for either variable, but I'd get fractions, and solving the second equation for x would also give me fractions. It wouldn't be "wrong" to make a different choice, but it would probably be more difficult. Being lazy, I'll solve the second equation for y:
4x + y = 24
y = –4x + 24
Now I'll plug this in ("substitute it") for "y" in the first equation, and solve for x:
2x – 3(–4x + 24) = –2
2x + 12x – 72 = –2
14x = 70
x = 5
26 percent of 200 is 52 :)
So let's leave the 112 aside for now. The question then becomes how to write the decimal 0.001 as a fraction. The key is to remember that
0.x corresponds to "tenths" so x/10
0.0x corresponds to "hundredths" --> x/100
0.00x corresponds to "thousandths" --> x/1000
The number 0.001 is just 1 thousandth, or 1/1000
Now back to 112.001. You can write it as
112/1 + 1/1000 =
(112,000+1)/1000 =
112,001/1000 (the fraction you were looking for)
Let me know if you have questions
<span> we know that the 90 percentile in Z-score is ≈ 1.28 then,
=136 ± 1.28(13.8)
=(118.336 , 153.664)
</span>hope it helps
