Solve 212-5*[a+3*(5*6-17)]=12

$$212 - 5 \times [ a + 3 \times ( 5 \times 6 - 17 ) ] = 12$$

Solve for a

$$a=1$$

Steps for Solving Linear Equation

Multiply 5 and 6 to get 30.

$$212-5\left(a+3\left(30-17\right)\right)=12$$

Subtract 17 from 30 to get 13.

$$212-5\left(a+3\times 13\right)=12$$

Multiply 3 and 13 to get 39.

$$212-5\left(a+39\right)=12$$

Use the distributive property to multiply -5 by a+39.

$$212-5a-195=12$$

Subtract 195 from 212 to get 17.

$$17-5a=12$$

Subtract 17 from both sides.

$$-5a=12-17$$

Subtract 17 from 12 to get -5.

$$-5a=-5$$

Divide both sides by -5.

$$a=\frac{-5}{-5}$$

Divide -5 by -5 to get 1.

$$a=1$$