Working alone it takes mark 7 hours to mop the whole house it takes sue 9 determine to the nearest hundredth of the hour how long it will take then to mop the house together

3.9375 hours

Step-by-step explanation:

Working alone it takes mark 7 hours to mop the whole house it takes sue 9 determine to the nearest hundredth of the hour how long it will take then to mop the house together

This is calculated as

1/Time it would take them to work together = 1/ Number of hours Mark mopped + 1/ Number of hours Sue mopped

= 1/T = 1/7 + 1/9

Lowest common denominator = 63

1/T = 9 + 7/63

1/T = 16/63

T = 63/16

T = 3.9375 hours

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