Answer:
The equation of the line is y = 7x - 10
Step-by-step explanation:
* Lets revise the form of the equation
- The form of the equation of a line is y = mx + c , where m is the slope
of the line and c is the y-intercept
- The y-intercept means the line intersect the y-axis at point (0 , c)
- The slope of the line which passes through points (x1 , y1) , (x2 , y2)
is 
* Lets solve the problem
∵ The y-intercept is y = -10
∴ The line intersects the y-axis at point (0 , -10)
∵ The line passes through the points (2 , 4) and (0 , -10)
- Lets find the slope of the line using the rule of the slope above
∵ 
∴ The slope of the line is 7
∵ c is the y-intercept
∵ The y-intercept is y = -10
∴ c = -10
∵ y = mx + c
∴ y = 7x + -10
∴ y = 7x - 10
* The equation of the line is y = 7x - 10