0.8(0.1a+0.3)=-0.8

Divide each term in 0.8(0.1a+0.3)=-0.8 by 0.8.

0.8(0.1a+0.3)0.8=-0.80.8

Cancel the common factor of 0.8.

0.1a+0.3=-0.80.8

Divide -0.8 by 0.8.

0.1a+0.3=-1

0.1a+0.3=-1

Subtract 0.3 from both sides of the equation.

0.1a=-1-0.3

Subtract 0.3 from -1.

0.1a=-1.3

0.1a=-1.3

Divide each term in 0.1a=-1.3 by 0.1.

0.1a0.1=-1.30.1

Cancel the common factor of 0.1.

a=-1.30.1

Divide -1.3 by 0.1.

a=-13

a=-13

Solve for a 0.8(0.1a+0.3)=-0.8