One way to do this problem is to determine the common difference. If the 5th and 8th terms are -9 and -21, we can do this by subtracting -9 from -21:
-21-(-9) = -12. The 5th and 8th terms are not consecutive, so we have to think in terms of (8-5), or 3, times the common difference to get from -9 to -21.
Note that -12 divided by 3 is -4. Thus, the common difference is -4.
Check: -9 - 4 = -13; -13 - 4 = -17; -17 - 4 = -21 (which is correct).
We know that the 5th term is -9. To find the 4th term, work backwards: subtract (-4) from -9, which produces -9+4=-5.
The fourth term is -5. Subtracting -4 from this (which is the same as adding 4 to this -5) produces the third term; it is -1. Can you now find the 2nd and 1st terms using the same approach?
Answer:
b = 4
General Formulas and Concepts:
<u>Pre-Algebra</u>
- Order of Operations: BPEMDAS
<u>Algebra I</u>
Step-by-step explanation:
<u>Step 1: Define equation</u>
8b - 12 = 5b
<u>Step 2: Solve for </u><em><u>b</u></em>
- Subtract 5b on both sides: 3b - 12 = 0
- Add 12 on both sides: 3b = 12
- Divide 3 on both sides: b = 4
<u>Step 3: Check</u>
<em>Plug in b to verify it's a solution.</em>
- Substitute: 8(4) - 12 = 5(4)
- Multiply: 32 - 12 = 20
- Subtract: 20 = 20
And we have our final answer!
Answer:
18x
Step-by-step explanation:
get the x by itself then it is 2+4=6 so that is 6x and then do 3+x=3x and 6x×3x= 18x
