
find/make C subject
a= 3
b= 2
d= 5
a=4b + (6/ c1) 15d
okey so il show how far i am. could someone please tell me where im goin wrong. many thanks
3= (8) + (6/ C1)  75
75+3 = 8+ (6/ C1)
78 = 8 + (6/ C1)
788 = (6/C1)
70 = (6/C1)
C1 (70) = 6
C (70) = 7
C= (7/70)
C= 0.1

You're right until the fourth line up from the bottom. If (c1) definitely has brackets round then 6=70(c1) you need to multiply out to get 6=70c70 then rearrange. You should get c=76/70 = 1.1 approx

but if i then subsitute 1.1 value for C then the answer should equal a= (3)?

don't sub in 1.1 (the answer is really 1.0857....) as this is the rounded up answer. if you put c=76/70 into the original equation then you will get a=3.

Quote:
Originally Posted by
decoy808 a=4b + (6/ c1) 15d
You were told by Willow T that your bracketing is faulty; should be:
a = 4b + 6 / (c1)  15d
Now rearrange:
6 / (c1) = a  4b + 15d
c  1 = 6 / (a  4b + 15d)
c = 6 / (a  4b + 15d) + 1

Analysis
Hi ineed to solve this exercise. Who can help me?
Let A subset of R (real numbers) A no empty. A is annotated if and only if exist M (positive rel) such that absolute value of x is less than or equal that M, for all x in A