Answer:
Consider f: N → N defined by f(0)=0 and f(n)=n-1 for all n>0.
Step-by-step explanation:
First we will prove that f is surjective. Let y∈N be any natural number. Define x as the number x=y+1. Then x∈N, and f(x)=x-1=(y+1)-1=y. We conclude that f is surjective.
However, f is not injective. Take x1=0 and x2=1. Then x1≠x2 but f(x1)=0 and f(x2)=x2-1=1-1=0. We have shown that there are two natural numbers x1,x2 such that x1≠x2 but f(x1)=f(x2), that is, f is not injective.
Note:
If 0∉N in your definition of natural numbers, the same reasoning works with the function f: N → N defined by f(1)=1 and f(n)=n-1 for all n>1. The only difference is that you consider x1=1, x2=2 for the injectivity.
It cant be 7 because,
X-7>3
7-7>3
0>3
And 0 is not bigger than 3
It cant be 9 because,
X-7>3
9-7>3
2>3
And 2 is not bigger than 3
So it is 11 because,
X-7>3
11-7>3
4>3
And 4 is bigger than 3
So the answer is 3) 11
About 50 miles. hope this helps!
There is no answer, the equation is false.
Answer:
x=-8 and y=9
Step-by-step explanation:
rewrite the equations to x+2y=10,3x+4y=12
sub 2y from both sides x+2y-2y=10-2y
substitue x=10-2y in 3x +4y=12
3(-2y+10)+4y=12
distribute
add-30 to both sides
divide both sides by -2
y=9
sustitute 9 for y in -2y+10=x
x=-8
