I will see that 12x-6 will equivalent to 90° because both angle add together to get 180° and each of them has 90° each which is complementary angel, so here is the equation: 12x-6=90 Add 6 to each side 12x-6+6=90+6 12x=96 Divided both side by 12 12x/12=96/12 x=8 To prove x is correct, I will give you another way to et the same answer. We see that 12x-6 and 90° formed the straight line which add up to total of 180°, so 12x-6+90=180 12x+84=180 Subtract 84 to each side 12x+84-84=180-84 12x=96 Divided both side by 12 12x/12=96/12 x=8. As a result, the correct answer is 8. Hope it help!
