7 I think because if you would put a zero behind the 4 and 7 and add them together it will be 110 and all that's left if u subtract them from 180 is 70 (7)
First we will calculate rate of work of rosa and amy.
work done by rosa in time t=t*1/7
Work done by Amy and rosa=t(1/7+1/4.2)
t/7+t/a=t/4.2
t=10.5 hr
Always keep remember those formula or logic belowWork rate × Time to finish the job = 1 job done
Work rate = (1 job done) / (Time to finish the job)
Time of doing the job = (1 job done) / (Work rate)
2+2=4 because if you have 2 and you add another 2 you will have 4
Substitue 2x for y in the second equation:
Rearrange to
form:
Factor:
Zeros are
and
To find y-coordinates of pts of intersection, plug these x-values into first equation to get
and
Literally just replace the nine and four with ANY other numbers.
