Q28 of 137 Page 100

Evaluate {(7.8)2 – (2.2)2}.

We have,


{(7.8)2 – (2.2)2}


By using the formula a2 – b2 = (a + b)(a – b)


We get,


{(7.8)2 – (2.2)2} = (7.8 + 2.2)(7.8 – 2.2)


= (10 × 5.6)


= 56


So,


{(7.8)2 – (2.2)2} = 56


More from this chapter

All 137 →
26

Factories:

100 – (x – 5)2

 27

Evaluate {(405)2 – (395)2}

 1

Factorize:

x2 + 8x + 16

 2

Factorize:

x2 + 14x + 49