11, add six and a half to four and a half.
Lets round it to the nearest ten
A 97 ====> 100
B 118 ===> 120
C 179 ===> 180
D 5091 ==> 5090
No result yet, lets round to the nearest hindred.
A 97 ====> 100
B 118 ===> 100
C 179 ===> 180
D 5091 ==> 5100
As we can see only A give the same result when we round it to the nearest hundred and nearest ten.
total of ages now is 67 + 4 + 4 = 75
S=shelly
M= Michelle
Michelle is 3 yrs younger than Shelly so use S-3
S +M = 75
replace M with S-3 to get:
S +S-3=75
2S=78
s=39
So shelly is 39
Michelle is 3 years younger = 39-3 = 36
I only know how to do a, so i hope i can help a little bit.
y=mx+b
-2=-3(7)+b
-2=-21+b
b=19
so your equation is y=-3x+19
i hope this helps!!