The equation for a straight line graph is y = mx + b, where m is the slope (or gradient) of the line and b is the y-intercept (where the line crosses the y-axis).
To convert a curved line into a straight line graph, you can take the inverse of the x-values and plot them on the y-axis. In this case, the equation y = 85x^(-1) would become y = 85/x. This will result in a straight line graph.
The exponent in the equation y=85x^(-1) represents the power to which the variable x is raised. In this case, x^(-1) means that x is being raised to the -1 power, which is the same as taking the reciprocal of x.
The slope of a straight line graph can be found by taking any two points on the line and using the formula (y2-y1)/(x2-x1), where (x1, y1) and (x2, y2) are the coordinates of the two points. This will give you the slope, or gradient, of the line.
The y-intercept in a straight line graph is the point where the line crosses the y-axis. It represents the value of y when x is equal to 0. In the equation y = mx + b, the y-intercept is represented by the variable b. It can give information about the starting point or initial value of a relationship between two variables.