Sugar: x pounds
flour: 2x + 5 pounds
2x + 3(2x + 5) = 40
2x + 6x + 15 = 40
8x = 25
x = 3.125
-> a sack of flour is 3.125 + 5 = 8.125 pounds
I hope it‘s coorect
This is known as Einstein's proof, not because he was the first to come up with it, but because he came up with it as a 15 year old boy.
Here the problem is justification step 2. The written equation
BC ÷ DC = BC ÷ AC
is incorrect, and wouldn't get us our statement 2, which is correct.
For similar triangles we have to carefully pair the corresponding parts to get our ratios right:
ABC ~ BDC means AB:BD = BC:DC = AC:BC so BC/DC=AC/BC.
Justification 2 has the final division upside down.
Answer:
c)
Step-by-step explanation:
Use 49 instead of 14 for 7²
Reason: 7² = 7 * 7 = 49
Not 14 as 7*2 = 14
