x + (x*2.5) = 70
How would you solve for x? Steps please?
Answers (2)
Recall for any (real) numbers a, b and c
a*(b + c) = (a*b) + (a*c)
For example if a=2, b=3, and c = 5
a*(b+c) = 2*(3 + 5) = 2*8 = 16
(a*b) + (a*c) = (2*3) + (2*5) = 6 + 10 = 16
Since we easily see that
x+ (x*2.5) = 70
is the same as
(x*1)+(x*2.5) = 70
Using the above rule we see that this is the same as
x*(1+2.5) = 70
Simplifying we have
x*3.5 = 70
dividing by 3.5 on both sides we get
x = 70/3.5 = 20
Well x is a letter that symbolises something. Let's think of it as if it were a physical problem. Say, calculate the weight of a potato.
1 Potato + 2. 5 potato = 70 grams
So 3.5 potatoes = 70 grams
So now we divide both terms by 3.5
1 potato therefor weights 20 grams.
Now in your math class we have abstracted this. So we use X, because as long as the equation holds true it will be 20.
1 x + 2.5 x = 70
(1+2.5) x = 70
x = 70/(3.5)
X= 20