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:
Step-by-step explanation:
The complete question in the attached figure
we know that
The <u><em>Triangle Exterior Angle Theorem</em></u> states that: An exterior angle of a triangle is equal to the sum of the opposite interior angles.
In this problem
solve for x
Jamal-3 x 3 = 9 x 4 = 36
Andy- 4 x 2 = 8 x 5 = 45
Andy's surface area is bigger.
I think that is right I look it up and god bless have a great day
Answer:
Step-by-step explanation:
1) translate the given informations in a operation
8x^2 -7x - 2 - (6x^2-x+3)
2) change the sign of all the terms in the bracket
8x^2 -7x -2 -6x^2 + x -3
3) simplify the expression
2x^2 - 6x -5
