So even postive integers are by defention in form 2k where k is a natural number so
let the sum of even integers to n=S
S=2(1+2+3+4+5+6+7+8+......+k-1+k
divide bith sides of equation 1 by 2
0.5S=1+2+3+4+5+...........+k-1+k
S=2(k+(k-1)+..............................+2+1)
divide both sides of equation 2 by 2
0.5S=k+k-1+..............................+2+1)
by adding both we will get
___________________________
S=(k+1)(k)
so the sum will be equal to
S=

so let us test the equation
for the first 3 even number there sums will be
2+4+6=12
by our equation 3^2+3=12
gave us the same answer so our equation is correct
Answer:
x<7
Step-by-step explanation:
12x>9(2x-3)-15
12x>18x-27-15
12x>18x-42
-6x>-42
x<7
Answer:
x=-(9+1y)/2
y=-2x-9
Step-by-step explanation:
2x=-9-1y
x=-(9+1y)/2
-1y=2x+9
y=-2x-9
Answer:
It is B.
Step-by-step explanation:
No two same inputs or x are for the y.
-2=-5 + 6
Sorry if I’m wrong