Quick combining terms clarification

[nortski]

Hi guys, when combining negative like terms such as -3x -4x will give -7x. Does that mean that there's a hidden + between them?

 

[pka]

Hi guys, when combining negative like terms such as -3x -4x will give -7x. Does that mean that there's a hidden + between them?

Hidden? Well really it is maybe a short-cut: $-3-4=(-1)(3+4)=(-1)(7)=-7$. Do you see the logic there?

 

[Dr.Peterson]

Hi guys, when combining negative like terms such as -3x -4x will give -7x. Does that mean that there's a hidden + between them?

A better way to think of it is that we define subtraction as addition of the opposite (negative): a - b means a + (-b).

So when we write -3x - 4x, that means (-3x) + (-4x). Not exactly "hidden", but implied. And often, seeing it in the latter way helps in carrying out the work.

 

[nortski]

Thanks guys, that's cleared things up for me

 

[firemath]

Thanks guys, that's cleared things up for me

It's good to watch things be cleared.

From the corner.