I actually posted this a while ago and it got answerd by a smart person so here's what I understood
the error is that it assumes that √(x²)=x
because if x is negative, it becomes positive
that's how the 2nd line is wrong
the 2nd line is the first wrong step
it goes from 4-9/2+9/2
so it goes from 4-4.5+4.5
notice the part under the parenthsees
√((4-4.5)²)
if we evaluate 4-4.5, we get -0.5
but by squaring it we get 0.5
-0.5+4.5=4, yes
but when we square it we get
0.5+4.5=5, that is how it works
The answer is 15.
Also if the first is the same the second is obviously the same
Let x and y represent the numbers of gallons used by the 40 mpg and 35 mpg cars, respectively.
.. x +y = 40 . . . . . . . . . . .total consumption is 40 gallons
.. 40x +35y = 1525 . . . . total miles driven = 1525
Multiply the first equation by 40 and subtract the second.
.. 40(x +y) -(40x +35y) = 40(40) -(1525)
.. 5y = 75
.. y = 15
.. x = 40 -15 = 25
The 40 mpg car consumed 25 gallons.
The 35 mpg car consumed 15 gallons.
Answer:
x
2
+
2
x
−
15
Step-by-step explanation:
