#### Answer

$= -.56$

#### Work Step by Step

We follow order of operations, so we first consider exponents, and then, starting on the left and going right, we do addition and subtraction.
$=-0.4^{2} + 0.3^{2} - 0.7^{2}$
$= -0.16 + 0.09 - 0.49$
$= -.07-.49$
$=-.56$