#### Answer

$x \approx 4.8$

#### Work Step by Step

$(x+2)(x+1)=40$
$x^2+3x+2=40$
The value of $b$ is 3.
The term to add to $x^2+3x$ is $(\frac{3}{2})^2=\frac{9}{4}$
$c=\frac{9}{4}$
Complete the square:
$x^2+3x+\frac{9}{4}=40+\frac{1}{4}$
$(x+\frac{3}{2})=\frac{161}{4}$
$x+\frac{3}{2}=6.3$
$x \approx 4.8$