Answer:
25x - 45 = 5(5x - 9)
Step-by-step explanation:
Find the greatest common factor (GCF) of 25 and 45.
You can do this several ways, but one way is to list all the factors of both numbers and find the greatest common one:
Factors of 25: 1, 5, 25
Factors of 45: 1, 3, 5, 9, 15, 45
Therefore, 25 and 45 have 2 common factors: 1 and 5
So the greatest common factors is 5
25x - 45 = 5(ax - b)
To find the value of a, simply divide 25 by 5: 25 ÷ 5 = 5
To find the value of b, divide 45 by 5: 45 ÷ 5 = 9
25x - 45 = 5(5x - 9)
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:
D prefer romance over poetry 2:1
Step-by-step explanation:
Poetry is 20%
Romance is 40%
Answer:
ABD
Step-by-step explanation:
Answer: it is 6
Step-by-step explanation: because they are the same length.
