Step-by-step explanation:
the scanned description is very hard to understand.
so I think what happened :
16x² - 9 = 16
then the first error :
sqrt(16x²) - sqrt(9) = sqrt(16)
that is wrong, as you cannot split a + or - operation inside a sqrt function into + or - separate sqrt results of the parts.
so, correctly, the only possible transformation involving sqrt for both sides :
sqrt(16x² - 9) = sqrt(16)
but it would be even easier to clean up the various constant numbers with each other.
so,
16x² - 9 = 16
16x² = 25
and now we trashes the square root
sqrt(16x²) = sqrt(25)
4x = 5
x = 5/4 or x = -5/4
and I cannot see or understand for my life what the second equation was, as Daniel did something wrong, so I cannot deduct the original equation out of a supposedly wrong
y³ - 1 = 7
Answer:
x = 1.9
Step-by-step explanation:
Thanks to a theorem we can use this proportion
10.47 : 4.44 = 4.44 = x
x = (4.44^2)/10.47 = 1,882865 = 1.9
Answer:
10 cm
Step-by-step explanation:
If we assume that DC is parallel to AB, then triangle DOC is similar to triangle AOB.
However, even with this assumption, there is not enough information in the diagram to solve for DO. We would also need to know the length of CO. Then we could write a proportion:
DO / (DO + 20) = CO / (CO + 24)
Edit: OD is 2 cm shorter than OC. If we call x the length of OD, then the length of OC is x+2.
Putting this into our proportion:
x / (x + 20) = (x + 2) / (x + 2 + 24)
x / (x + 20) = (x + 2) / (x + 26)
Cross multiply:
x (x + 26) = (x + 2) (x + 20)
Distribute:
x² + 26x = x² + 20x + 2x + 40
x² + 26x = x² + 22x + 40
4x = 40
x = 10
So the length of DO is 10 cm.
