We'll use Cramer's rule for 2 equations:
ax + by = e
cx + dy = f
5x -3y = 18 a=5 b=-3 e=18
2x + 7y = -1 c=2 d=7 f=-1
denominator determinant (dn) = (a * d) - (c * b) = 5 * 7 - (2 * -3) = 41
x = [(e * d) - (f * b)] / dn
[18 * 7 - (-1 * -3)] / 41 =
123 / 41 = 3
y = [(a * f) - (c * e)] / dn
= (5 * -1) -(2 * 18) / 41 =
-41 / 41 = -1
Source:
1728.com/cramer.htm
Answer:
7/20
Step-by-step explanation:
first of all you have to put the two fractions on the same denominators
1/4 (multiply by 5) and you will get 5/20
2/5(multiply by 4) and you will get 8/20
we have to add 5/20 and 8/20 that gives us 13/20
13/20 is the amount he drank
20/20 - 13/20 =7/20
7/20 is the amount of water left that Charlie has left
The values of the functions are -1/ 4, 3/ 16 and 3/ 8 respectively.
<h3>What is a function?</h3>
A function is a rule or expression showing the relationship between a dependent and independent variable.
We have the function to be;
f(x) = 3/ 4(x + 2)
Let's find f(-5), substitute the value of x as -5
f(-5) = 3/ 4 ( -5 + 2)
f(-5) = 3/ 4 × -3
f(-5) = -1/ 4
f(2), substitute the value of x as 2
f(2) = 3/ 4(2 + 2)
f(2) = 3/ 4 (4)
f(2) = 3/ 16
f(4) = 3/ 4 ( 4 + 2)
f(4) = 3/ 4(6)
f(4) = 3/ 8
Thus, the values of the functions are -1/ 4, 3/ 16 and 3/ 8 respectively.
Learn more about functions here:
brainly.com/question/4025726
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Answer:
hi there!
the correct answer to question is: x=-3
Step-by-step explanation:
you move -12x to the other side by adding it on both sides to get: -3x=9 then you divide -3 on both sides to get x=-3
