QUADRATICS A3

Show that  4w² – 20w + 25=0  is a perfect square.

Solution  

a=4, b=-20, c=25. 

We use the formula: b² = 4ac.

b² = 4ac.

(-20)² = 4 x 4 x 25

(-20 x -20) = 4 x 4 x 25

+400 = 16 x 25

+400 = +400

LHS = RHS. Hence shown!   

 

TRY THIS…….            

Show that  9w² – 30w + 25=0  is a perfect square.