Answer: 11/4 x 7 = 11/2 ; 3/35 x 7 = 3/5 ; 5/7 x 7 = 5. So, the last three you listed work with 7 in the blank.
Standard form would be 1.46e-6 because the variable has one degree and the number 6 does not have a degree.
5(2x - 4) = 45
10x - 20 = 45
10x = 45 + 20
10x = 65
x = 65/10 reduces to 13/2 or 6 1/2
