[EDIT: Replaced x by * since x doesn't look well in typefaced math]
To find the discount rate you must first, multiply the RATE by the original price. Then to find the sale price, subtract the DISCOUNT from the original price.
Answer: Choice B
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Explanation:
The original equation is 
with 8 as the base. That is also the base of the log when we get the final answer shown above. Logs are useful to isolate the exponent.
The general rule is that 
is equivalent to the log form of 
where b is the base of each.
Y = -x + 4
y = 3x + 3
3x + 3 = -x + 4
3x + x = 4 - 3
4x = 1
x = 1/4
y = 3x + 3
y = 3(1/4) + 3
y = 3/4 + 3
y = 3/4 + 12/4
y = 15/4
solution is (1/4,15/4)
so line y = -x + 4 intersects the line y = 3x + 3 at (1/4,15/4)
Try breaking these into sections.
Twice: 2 times
The sum of: add
A number: choose a variable, like x
---Thus "the sum of a number and 4" becomes "add x and 4" which, mathematically, is "x+4"
-----Continuing to put it all together, "Twice the sum of a number and four" becomes "2 times (x+4)" which, mathematically, is "2(x+4)"
Is: equals
-------"Twice the sum of a number and four is" becomes "2(x+4)="
23 less than: subtract 23. This one tends to trick people; "23 less than" will become "__ - 23", NOT "23 - __"
three times the number: 3 times x
---"23 less than three times the number" becomes "subtract 23 from 3 times x" which, mathematically, is "3x-23"
-------So the final phrase: 2(x+4)=3x-23"
