First term ,a=4 , common difference =4-7=-3, n =50
sum of first 50terms= (50/2)[2×4+(50-1)(-3)]
=25×[8+49]×-3
=25×57×-3
=25× -171
= -42925
derivation of the formula for the sum of n terms
Progression, S
S=a1+a2+a3+a4+...+an
S=a1+(a1+d)+(a1+2d)+(a1+3d)+...+[a1+(n−1)d] → Equation (1)
S=an+an−1+an−2+an−3+...+a1
S=an+(an−d)+(an−2d)+(an−3d)+...+[an−(n−1)d] → Equation (2)
Add Equations (1) and (2)
2S=(a1+an)+(a1+an)+(a1+an)+(a1+an)+...+(a1+an)
2S=n(a1+an)
S=n/2(a1+an)
Substitute an = a1 + (n - 1)d to the above equation, we have
S=n/2{a1+[a1+(n−1)d]}
S=n/2[2a1+(n−1)d]
Answer:
1/3 / 1/3
1/3 x 3/1
= 1
Step-by-step explanation:
Answer:
I gave you most of the answer. I'll let you check my work and find the point using the solution.
Step-by-step explanation:
The first thing we do is we divide by negative one in the first equation to get
y = -x.
-3x + 3y = -36
Plug in y = -x and get
-3x + 3(-x) = -36
= -3x - 3x = -36
This equals -6x = -36
divide both sides by -6 and you get 6. 6 is your x value
Plug 6 back in to the second equation.
-3x + 3y = -36
-3(6) + 3y = -36
-18 + 3y = -36
3y = -18
y = -6
Answer:
6
Step-by-step explanation:
1)6-6=0
2)2(6-6)
2*0
0
x=6
Answer:
For me i just guess lol i dont know the correct answer i just telling you the truth
Step-by-step explanation:
