Answer:
Step-by-step explanation:
http://www.mrbartonmaths.com/resources/GCSE%20Revision/GCSE%20Maths%20Takeaway/2.%20Grade%20D/46.pdf
You can find it in this site
<span>Solve the system
9x = 27-9y
20x=71-9y
Let's use the "elimination through addition/subtraction method.
Multiply the first equation by -1 so as to obtain +9y:
-9x = -27 + 9y
</span><span>20x= 71- 9y
--------------------
Add these 2 equations together:
</span>-9x = -27 + 9y
20x= 71- 9y
--------------------
<span> 11x = 44
Solve this for x: x = 44/11 = 4.
Now find y by subst. 4 for x in either of the original equations.
Using the second equation: </span><span>
</span>20x=71-9y
20(4) = 71 - 9y
80-71 = -9y
9 = -9y. Then y = -1.
The solution set is (4,-1).
Answer:
x = ± 10
Step-by-step explanation:
to solve the equation let y = 0 , that is
100 - x² = 0 ( add x² to both sides )
100 = x² ( take square root of both sides )
± = x , that is
x = ± 10
Answer:
Step-by-step explanation:
Approximately $307.73 is the total amount of interest earned for 5 years at an annual interest rate of 4.5%, with an initial investment of $1,250.