For the following system if you isolated x in the second equation to use the substitution method what expression would you substitute into the first equation?
2x+y= 8
-х – зу = -12

a. зу + 12
b.-3y + 12
c. зу – 12
d.-3y - 12

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.