Y = 7x + 4 where x is the number of weeks Anna saves and y is the total amount in her account

X= 4/7 or =0.57143

Step-by-step explanation:

1.1 Solve y-7x+4 = 0

Tiger recognizes that we have here an equation of a straight line. Such an equation is usually written y=mx+b ("y=mx+c" in the UK).

"y=mx+b" is the formula of a straight line drawn on Cartesian coordinate system in which "y" is the vertical axis and "x" the horizontal axis.

In this formula :

y tells us how far up the line goes

x tells us how far along

m is the Slope or Gradient i.e. how steep the line is

b is the Y-intercept i.e. where the line crosses the Y axis

The X and Y intercepts and the Slope are called the line properties. We shall now graph the line y-7x+4 = 0 and calculate its properties

Graph of a Straight Line :

Calculate the Y-Intercept :

Notice that when x = 0 the value of y is -4/1 so this line "cuts" the y axis at y=-4.00000

y-intercept = -4/1 = -4.00000

Calculate the X-Intercept :

When y = 0 the value of x is 4/7 Our line therefore "cuts" the x axis at x= 0.57143

x-intercept = 4/7 = 0.57143

Calculate the Slope :

Slope is defined as the change in y divided by the change in x. We note that for x=0, the value of y is -4.000 and for x=2.000, the value of y is 10.000. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of 10.000 - (-4.000) = 14.000 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)

Slope = 14.000/2.000 = 7.000

Geometric figure: Straight Line

Slope = 14.000/2.000 = 7.000

x-intercept = 4/7 = 0.57143

y-intercept = -4/1 = -4.00000