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:
(B) is the answer according to my calculations
Step-by-step explanation:
Equations b,c, and e accurately represent this statement.
<h3>What is the equation?</h3>
A mathematical statement consisting of an equal symbol between two algebraic expressions with the same value is known as an equation.
The three equation accurately represents this statement is;
4.9 x-(-3) = 12.8
3+ 4.9 x = 12.8
12.8 = 4.9 x +3
Hence, equations b,c, and e accurately represent this statement.
To learn more, about equations, refer;
brainly.com/question/10413253
#SPJ1
Answer:
fx) = 
Step-by-step explanation:
1. step:
solve the bracket
fx) = 3(
- 1) 2 + 5
2. step:
use the BEDMAS form.
fx) = 
fx) =
Answer:
c
Step-by-step explanation:
because 3 x 3 = 9
1 x 5 = 5
simplest form will be 1 4/5
