3x - 18 = 42
3x = 42 + 18
3x = 60
x = 60/3
x = 20
Answer:
Step-by-step explanation:
Good at what?
Answer:
The subtraction property of equality
Option A is correct
Explanation:
The given equation is:
12 - x = 7x + 32
Subtract 12 from both sides
12 - 12 - x = 7x + 32 - 12
-x = 7x + 20 (Step 1)
From step 1 above, subtract 7x from both sides
-x - 7x = 7x - 7x + 20
-8x = 20 (Step 2)
Since we subtracted 7x from both sides to get step 2, the justification for step 2 is the subtraction property of equality
The amount an investment of 16000 grows over 7 years is 16000*0.12 (i.e., 12% of 16000). So, the total amount after 7 years is 16000 + 16000*0.12, which is the same as writing 16000*1.12. Now, continue the same argument: the amount we now have 16000*1.12 grows after another 7 years to (16000*1.12)*1.12. Third 7-year period, again, (16000*1.12*1.12*)*1.12, and so on. As you can already see the number of periods shows up as the number of factors 1.12 multiplied here. A shorthand for writing that is to use the exponent, like this
.
Generalizing to n 7-year periods yields a formula:
