Question

What number should be added to x2

+8x to get (x +4)2

?​

Answer 1

Answer:

16

Step-by-step explanation:

First let's expand $(x+4)^2$.

$(x+4)^2=x^2+8x+16$

Hence we should add $16$ to $x^2+8x$ to get $(x+4)^2$.

Answer 2

$x {}^{2} + 8x = (x + 4) {}^{2}$

$x {}^{2} + 8x = x {}^{2} + 16 + 8x$

$x {}^{2} - x {}^{2} + 8x - 8x = 16$

16 should be added to get

$(x + 4) {}^{2}$