Hi there! To solve this question, we can just simply multiply 3 1/8 and 5, because we're looking for the total length of the board, before it was cut into 5 equal pieces. To multiply fractions, just do it straight across. Numerator * numerator / denominator * denominator. 3 1/8 as a mixed number is 25/8 and 25/8 * 5/1 is 125/8 or 15 5/8 in mixed number form. There. The board was 15 5/8 inches long. The answer is D.
So just your normal equation.
We need to isolate x alone.
First lets write out our equation
3 +7x = 12
Lets do this step by step.
first subtract 3 from both sides.
3 + 7x = 12
-3 = -3 it cancels out on the left side and we solve on the right side.
*************
7x = 9
second we divide both sides by 7
7x = 9
÷7 = 7 we got the x alone and we just write 9/7 as our answer.
x = 9/7
Or as a decimal.
9/7 could be <span>1.28571428571429
</span>
Either will work.
x = 9/7
or
x = <span>1.28571428571429
</span>
Have a nice day. :)
