Question

what must be added to 4 x square + 20 X + 16 so that it becomes a perfect square​

Answer 1

Answer:

9 ✔

Step-by-step explanation:

4x^2+20x+16

(2x)^2 + 2 × 2x × 5 + 25 = (2x+5)^2

so ...

25-16 = 9

so 9 must be added to get a perfect square.!

Answer 2

Answer:

9

Step-by-step explanation:

4x²+20x+16

= [(2x)² + 2 × 2 × 5 ]+ 16

the bracketted part is of the form: a² +2ab, b² must be added to make it a perfect square,

but in 5²=25, 16 is already present

so, we only have to add, 25-15=9

on adding 9,

(2x)²+2×2×5+9+16

=(2x)²+2×2×5+25

=(2x+5)²

which is a perfect square