y=2
Step-by-step explanation:
Make an equation of straight line by using the formula :y= mx+c
put the x-value of point (2,4) which is 2 and the gradient,m which is 2 into the straight line equation:
y=2x +c
So you need to find the y-intercept to complete the equation, therefore:
when y=0,
0=2(2)+c
c=-4
next the question ask to find the y-coordinate when x =3, therefore you just need to replace x in the equation with 3:
y=2(3)-4
y=4
Answer = $39.78
100-20 =80
100-25=75
Multiply 60 x .80 to get $48
Then multiply 48 x .75 to get $36
Sales tax %10.5 = move decimal two places to left .105
Now multiply 36 x .105 =3.78
$3.78 equals your sales tax
Finally add $3.78+$36= $39.78
