A city has 3 new houses for every 7 old houses. If there are 21 new houses in the city, how many old houses are there A. 49
B. 47
C. 52
D. 51

A. 49

Step-by-step explanation:

ratio of houses is 3 new to 7 old

21 new is 7 times more than 3, so 7 will also be 7 times more

so, 21 to 49

I hope that made sense

answer: 19 is   2

step-by-step explanation: i just looked at your answer and wrote it down

x =-.20752

step-by-step explanation:

4^(x+2)=12

4^(x+2)=12

take the log base 4 on each side

log 4 (4^(x+2) = log 4(12)

we know log b(a^y) = y log b (a)

(x+2) log 4(4) = log 4 (12)

x+2 = log 4 (12)

we know   logb c = loga c/loga b

we want to convert to base 10   so a = 10

by default, we do not write the 10   c = 4   and b = 10

log4 10 = log 12/log 4

log4 10 = log 12/ log 4

x+2 = log 12/ log 4

subtract 2 from each side

x +2 -2 = log 12/ log 4 -2

x = 1.79248125 -2

x =-.20752