Sum/difference:
Let
This means that
Now, assume that 
is rational. The sum/difference of two rational numbers is still rational (so 5-x is rational), and the division by 3 doesn't change this. So, you have that the square root of 8 equals a rational number, which is false. The mistake must have been supposing that was rational, which proves that the sum/difference of the two given terms was irrational
Multiplication/division:
The logic is actually the same: if we multiply the two terms we get
if again we assume x to be rational, we have
But if x is rational, so is -x/15, and again we come to a contradiction: we have the square root of 8 on one side, which is irrational, and -x/15 on the other, which is rational. So, again, x must have been irrational. You can prove the same claim for the division in a totally similar fashion.
Answer:
5/7 is the only one
Step-by-step explanation:
Answer:
25 girls
Step-by-step explanation:
Let
x denote number of boys
and
y denote number of girls
According to the statement that total 45 people came,
x+y = 45 => Eqn 1
And total paid amount was 175
So,
5x + 3y = 175 => Eqn 2
For solving, We will use the substitution method
So, from eqn 1
x = 45-y
Putting value of x in eqn 2
5(45-y) +3y = 175
225 - 5y + 3y = 175
-2y+225 = 175
-2y = 175-225
-2y = -50
2y = 50
y = 25
Putting y =25 in eqn 1
x+25 = 45
x = 45 - 25
x = 20
As y= 25
So, 25 girls came to the dance ..
Answer:
i believe the answer would be B
Step-by-step explanation:
