Answer:The sitting fee is 15 dollars
Step-by-step explanation:If you were to use the formula y=mx+b then the starting equation would be y=12x+b. It already gave you the cost for the amount of photos respectively so 51=12(3)+b. 12 times 3 equals 36 and 51 minus 36 equals 15. The same way would be used for 87 dollars and 123 dollars while using the amount of photos respectively. 87=12(6)+b. 12 times 6 equals 72. 72 plus 15 equals 87. 123=12(9)+b. 12 times 9 equals 108. 108 plus 15 equals 123. Therefore the sitting fee is 15. (51=12(3)+15, 87=12(6)+15, 123=12(9)+15)
The required equation is y=12x+15.
The power of x is 1.
Given
Sitting fee =?
Portrait fee = $12.
For 3 photos $51 is charged including the sitting fee.
For 3 photos $36 is charged then
[tex]\begin{aligned} \rm Total\ Charged\ &=\ Sitting\ fee\ + 3\ photo\ fee\\51 &= sitting\ fee\ + 3*12\\51 &= sitting\ fee\ + 36\\\rm sitting\ fee\ &= 15\\\end{aligned}[/tex]
For 6 photos $87 is charged including the sitting fee.
For 6 photos $72 is charged then
[tex]\begin{aligned} \rm Total\ Charged\ &=\ Sitting\ fee\ + 6\ photo\ fee\\87 &= sitting\ fee\ + 6*12\\87 &= sitting\ fee\ + 72\\\rm sitting\ fee\ &= 15\\\end{aligned}[/tex]
For 9 photos $123 is charged including the sitting fee.
For 9 photos $108 is charged then
[tex]\begin{aligned} \rm Total\ Charged\ &=\ Sitting\ fee\ + 9\ photo\ fee\\123 &= sitting\ fee\ + 9*12\\123 &= sitting\ fee\ + 108\\\rm sitting\ fee\ &= 15\\\end{aligned}[/tex]
so,
[tex]y=mx+b\\y=12x+15[/tex]
y = total charged
x = number of photo
m = charger per photo
b = sitting fee
Thus, the required equation is y=12x+15.
More about the linear variable link is given below.
https://brainly.com/question/16548429
