solution: 16. Solve the equation below. \[ 12+x=-3(4-x) \] 17. Complete the equation so it solution of $x=2$. \[ 20 x-16=4 x+ \] 18. Complete the equation so it many solutions. \[ 0.3(6 x-5)=-1.5+ \]

Step 1 ：\(12 + x = -3(4 - x)\)

Step 2 ：\(12 + x = -12 + 3x\)

Step 3 ：\(2x = 24\)

Step 4 ：\(\boxed{x = 12}\)

Step 5 ：\(20x - 16 = 4x + 4\)

Step 6 ：\(16x = 20\)

Step 7 ：\(\boxed{x = \frac{5}{4}}\)

Step 8 ：\(0.3(6x - 5) = -1.5 + 0.3(6x - 5)\)

Step 9 ：\(\text{The equation has many solutions when it is an identity.}\)