If 5 times a number increased by 30 is 15, what is the number?

Number is -3

Step-by-step explanation:

5x + 30 =15

5x = 15 - 30

5x/5 = -15/5

x = -3

3/6   and 9/18

step-by-step explanation:

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)