-converting to a common denominator
The terms -c of the left side was converted to -4ac/4a to have the same denominator of b^2/4a.
A. the lower extreme is an outer but the upper exterme is not
120 cm=120 cm*(10 mm/1cm)=1200 mm,
Ratio: 1200 mm / 80 mm=15/1
Answer:
C. 15 to 1
Error = 60-50/50 × 100
= 10/50 × 100
= 20 %
