As a salesperson at roaring waves beach supplies, carissa receives a monthly base pay plus commission on all that she sells. if she sells $400 worth of merchandise in one month, she is paid $388. if she sells $700 of merchandise in one month, she is paid $454. find carissa's salary when she sells $2,600 worth of merchandise.

Base pay + (rate * sales) = total pay

b + r(400) = 388
b + r(700) = 454

b = 388 - 400r
now sub into 2nd equation
388 - 400r + 700r = 454
-400r + 700r = 454 - 388
300r = 66
r = 66/300
r = 0.22...22% is the rate

substitute for r
b + 400r = 388
b + 400(0.22) = 388
b + 88 = 388
b = 388 - 88
b = 300

so ur equation is : y = 0.22x + 300
y = 0.22(2600) + 300
y = 572 + 300
y = 872so her salary when selling $2600 worth of stuff is $872