The total cost in dollars,c, to have all 4 new tires put on a sports utility car is four times the cost of a tire, t, plus an additional charge of $84.00.

Question

how do you write an equation for this problem?

Answer 1

Yeah, it confused the dickens out of me when they started adding the alphabet to math. What in the world?? Let's see if we can make sense of this.

 

So, if a tire was $75, 4 tires would be 4(75) = 300, but you also have the extra $84. 300 + 84 = 384. Written all the way out, that's 4(75) + 84.

 

Buuuuut, a tire costs $t. 4 times t is simply written 4t, just like 4 of you would be 4 Cheryls.

 

We have to add the $84 charge. Like in 4(75) + 84, the 84 is separate, so 4t + 84.

 

Oooooh, an equation has an equal sign. We do things backward with equations like this, so the total goes first, or 384 = 4(75) + 84.

 

c = 4t + 84