will someone tell me the steps to solving the problem 21=2.5x+1 .......thank you

Question

lgbasallote · Answer

subtract 1 from both sides to make the constant on the right side zero...then divide both sides by 2.5 to isolate x

anonymous · Answer

when u  say subtract one from both sides do u mean 1 from 1 to make 0 and 1 from 21 ?

anonymous · Answer

My browser crashed. Now I need to write this all over again <_>

When solving an equation always collect similar terms to different sides so in the end you have x = something.

You do the collecting by - + -/- (dividing) or * (multiplying) both sides by a number or an unknown (a letter like x) and you divide BOTH sides that the equation holds true. You can put 3 apples to your left side and 3 apples to your right side and move them around on their separate sides and you can take 1 apple away from each side and the equality "=" still holds true, but if you take one apple away from the other side but not the other, the equation is not true anymore - the sides are not equal.

Now let's do this example you had.

21=2.5x+1 You see there's an extra +1 on the right side preventing us from having similar terms on each side. This is why you subtract 1, so put -1, on both sides to get 2.5x on the other side and 20 on the other side, like this

21=2.5x+1
21-1=2.5x-1
-> 20=2.5x

You now have a solution for 2.5x but you're looking for what 1x is equal to, so what 'x' is equal to. That is why you divide by 2.5x on both sides (equality rule) to get x on one side and something else on the other side. Remember that any number like 3 divided by itself, 3, is equal to one. That is why 2.5 divided by itself is 1, so 2.5x is equal to one multiplied by x, so 1x, so just x. Here is what I did then:

20=2.5x divide by 2.5x
20/2.5 = 2.5x / 2.5  (you can use a calculator for this, or just think that 2.5 goes to 20 eight, 8, times. 2.5+2.5+2.5+2.5+2.5+2.5+2.5+2.5 = 20 (eight times 2.5)
8 = x

-> x = 8

There's your answer : 3

lgbasallote · Answer

wow..you had to rewrite that o.O unlucky crash haha

anonymous · Answer

i wrote it fast and i did one mistake :D : there's "20=2.5x divide by 2.5x" but it's supposed to be just 2.5  :P