SOLUTION
Given the question in the image, the following are the solution steps to answer the question.
STEP 1: Represent the two coins
Let N represents Nickels
Let Q represents quarters
STEP 2: Get the first equation
Equation 1: Eric has 130 coins consisting of quarters and nickels. This is given as:
STEP 3: Get the second equation
The total value of all of the coins is $15.90. Each quarter represents .25 and each nickel represents .05, then the second equation is:
STEP 4: Multiply Equation 2 by 100 to remove the decimals
STEP 5: Make N the subject of Equation 1