Because 4.7 is the "abbreviation" for 4.70 also 4.7 is the simplified version of 4.70 kind of like a fraction you 4 70/100 simplified is 4 7/10 or 4.7.
By increasing the number of blue widgets supplied
-22 - x = 5 + 6x + 9 Combine like terms (5 and 9)
-22 - x = 14 + 6x Subtract 6x from both sides
-22 - 7x = 14 Add 22 to both sides
-7x = 36 Divide both sides by -7
x = 5