Answer:
X²+16x-63
Step-by-step explanation:
expand out the brackets to get:
X²+9x+7x-63
simplify:
X²+16x-63
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]
The area of the shaded part is 52 sq. inches. The correct option is b. 52 sq. inches
<h3>Calculating Area</h3>
From the question, we are to determine the area of the shaded part
In the given diagram, the shaded part is a rectangle
Area of a rectangle = Length × Width
Length of the shaded part = 18 inches - 4 inches - 1 inch = 13 inches
Width of the shaded part = 6 inches - 2inches = 4 inches
Then,
Area of the shaded part = 13 inches × 4 inches
Area of the shaded part = 52 sq. inches
Hence, the area of the shaded part is 52 sq. inches. The correct option is b. 52 sq. inches
Learn more on Calculating area here: brainly.com/question/12529348
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Step-by-step explanation:
4a + b²5
that's the answer hopes it helps!
