Answer is
$5gg+ $35 ≤ $55
Is your inequality statement
4 gg is the solution
Step by step
gg = gigabytes she can use and stay within budget
$5 is “x” or “gg”, the rate per gg
$35 is the one time fee
$55 is the output or y
Using y intercept form, y = mx + b
$5gg+ $35 ≤ $55
$5gg ≤ 55 -35
$5gg ≤ $20
gg ≤ 4 that she can use and stay within budget
** we used less than or equal to sign because we cannot spend over $55