Break down the fraction. 3 is the common denominator, so it is the denominator of both numerators.
27x/3 + 9/3 = 0 9x + 3 = 0 9x = -3 x = -3/9 simplified to x = -1/3
Or simply multiply the fraction with 3/1 to remove the denominator, which is 3. 27x + 9 3 27x + 9 ----------- x ------- = ----------------- or 27x + 9 = 0 ; look for x. 3 1 1
To check: Substitute x by its value: (27x + 9) / 3 = 0 ⇒ ((27 * -1/3) + 9) / 3 = 0 ⇒ (-9 + 9)/3 = 0 ⇒ 0/3 = 0 ⇒ 0 = 0
If you're saying that the scale is 10 cm: 1 mm then the scale will be larger than the actual object because for every 1 mm of the object it will equal 10 cm of the scale drawing.