Answer:
In a system, the substitution method is one of the 3 main ways to solve a system and can be very efficient at times.
<u>Skills needed: Systems, Algebra</u>
Step-by-step explanation:
1) Let's say we are given two equations below:
![y=4x \\ 4x-5y=-32](https://tex.z-dn.net/?f=y%3D4x%20%5C%5C%204x-5y%3D-32)
We can use substitution here by substituting in for
in the second equation. This means we put in
for
in the 2nd equation so we only have
variables in the equation, allowing us to solve for
.
2) Solving it out:
![1) 4x-5(4x)=-32 \\ 2) 4x-20x=-32 \\3) -16x=-32 \\4)x=2\\5)y=4x = 4(2) = 8 \\ 6)y=8](https://tex.z-dn.net/?f=1%29%204x-5%284x%29%3D-32%20%5C%5C%202%29%204x-20x%3D-32%20%5C%5C3%29%20-16x%3D-32%20%5C%5C4%29x%3D2%5C%5C5%29y%3D4x%20%3D%204%282%29%20%3D%208%20%5C%5C%206%29y%3D8)
We essentially substitute in that value as seen in step 1. Steps 2 and 3 are just simplifying the left side and allowing for us to solve. Step 4 is where we divide by -16 on both sides to solve for x. Step 5 and 6 show us solving for y using the value for x. We get ![x=2,y=8](https://tex.z-dn.net/?f=x%3D2%2Cy%3D8)
Answer: the rule is to add 1.5
3 + 1.5 = 4.5
4.5 + 1.5 = 6
6 + 1.5 = 7.5
etc...
Answer:
The Correct option is C ) 25
Therefore the value of x is 25 when y =40.
Step-by-step explanation:
Given:
Variable 'y' is directly proportional to the variable 'x'.
......Direct Variation
Where,
k = Constant of proportionality
To Find:
value of x = ? when y = 40
Solution:
First we need to find Constant of proportionality
When x = 20 and y = 32
Substituting the values we get
![32=k\times 20\\k=\dfrac{32}{20}=1.6\\\\k=1.6](https://tex.z-dn.net/?f=32%3Dk%5Ctimes%2020%5C%5Ck%3D%5Cdfrac%7B32%7D%7B20%7D%3D1.6%5C%5C%5C%5Ck%3D1.6)
Now when k =1.6 , y = 40 then x will be
![40=1.6\times x\\\\x=\dfrac{40}{1.6}=25\\\\x=25](https://tex.z-dn.net/?f=40%3D1.6%5Ctimes%20x%5C%5C%5C%5Cx%3D%5Cdfrac%7B40%7D%7B1.6%7D%3D25%5C%5C%5C%5Cx%3D25)
Therefore the value of x is 25 when y =40.
Answer:
![\frac{3}{2}t+15\leq 21](https://tex.z-dn.net/?f=%5Cfrac%7B3%7D%7B2%7Dt%2B15%5Cleq%2021)
Step-by-step explanation:
Let t represent the number of teachers.
We have been given that Noor gave 1/3 of a sheet to each of the 45 students at recess.
Let us find the number of sheets given to students by Noor by multiplying the total number of students by the part of sheet given to each student.
![\text{Number of sheets given to 45 students}=45\times \frac{1}{3}](https://tex.z-dn.net/?f=%5Ctext%7BNumber%20of%20sheets%20given%20to%2045%20students%7D%3D45%5Ctimes%20%5Cfrac%7B1%7D%7B3%7D)
![\text{Number of sheets given to 45 students}=15](https://tex.z-dn.net/?f=%5Ctext%7BNumber%20of%20sheets%20given%20to%2045%20students%7D%3D15)
So, Noor gave 15 sheets to 45 students.
We have been given that Noor wants to give
sheet to each teachers, so the number of sheets given to t teachers will be
.
As Noor has bought 21 sheets, so the number of sheets given to students and t teachers will be less than or equal to 21.
We can represent this information in an inequality as:
![\frac{3}{2}t+15\leq 21](https://tex.z-dn.net/?f=%5Cfrac%7B3%7D%7B2%7Dt%2B15%5Cleq%2021)
Therefore, the inequality
represents the number of teachers ,t, Noor could give sheets of stickers too.