Combination of 2 formulas for a graph

[Steve4Physics]

I would say number 3 and 4 are correct

No.

We are told x = (a+b)c.

We can choose any values we want for a, b and c. For example, suppose a= 1, b =2 and c = 5.

We can put the chosen values in so that we know what x is for our chosen values of a, b and c;
x = (a+b)c = (1+2)*5 = 3*5 = 15

Choice 3) is x = (a+c)b. This gives x = (1+5)*2 = 6*2 = 12. That’s not equal to 15! So choice 3) is wrong.

There is only one correct answer, choice 4), x = ac + bc = 1*5 + 2*5 = 5+10 = 15.

This is very basic maths. If you are on some sort of course which requires maths, you need to do some revision/catching-up. There’s plenty of online stuff available, for example BBC Bitesize Maths. Good luck.

 

[leejohnson222]

i appreaciate your assistance, yes i am on a course after a 15 year break from maths, and i know some of the basic rules are letting me down, with brackets etc, i actually did exactly this by substituing for numbers and went to work out all of the ones your wrote up, problem is its hard after a 10 hour day and sorting the kids out, anyway no excuse i need to improve here to progress. thanks again