Question Details

If the value of b=7, evaluate the expression (b+2)2+(b-2)2.

Options

A

18

B

22

C

24

D

20

Show Answer

Correct Answer :

Option B

22

Solution :

The correct answer is 22.

We are given that:
b=7
We need to find the value of the algebraic expression:
(b+2)2+(b-2)2

Step 1: Expand and simplify the expression algebraically
Recall the fundamental algebraic identity for the sum of two squared binomials:
(x+y)2+(x-y)2=2(x2+y2)

Expanding each term individually:
(b+2)2=b2+4b+4
(b-2)2=b2-4b+4

Adding the two expressions together:
(b+2)2+(b-2)2=(b2+4b+4)+(b2-4b+4)

Notice that the positive and negative middle linear terms
+4b
and
-4b
cancel each other out:
(b+2)2+(b-2)2=2b2+8

Step 2: Substitute the given value of b
Since we are given
b=7
squaring both sides yields:
b2=(7)2=7

Now, substitute
b2=7
into our simplified expression:
2b2+8=2(7)+8
=14+8
=22

Therefore, the evaluated result of the expression is 22.

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