Answer:
x intercept at x = -64/3
Step-by-step explanation:
The values in this table are given:
x -38 -23 -8
y 40 30 20
y = ax + b
a is the gradient (or slope).
b = y intercept, which is the pint on the y-axis, where the x coordinate = 0.
a = (-23 - -38) / (40-30) = 15/10 = 3/2
Rewrite to solve for b, which means rewrite so it starts with b = ...
b = y - 3/2 * x
Substitute one point ( -8, 20 )
b = 20 - (3/2 * -8)
b = 20 - ( -12)
b = 20 + 12
b = 32
So now we have the formula for the line:
y = 3/2*x + 32
To find the x intercept, you need to substitute y = 0
0 = 3/2*x + 32
3/2*x = -32
multiply left and right of the = with 2/3 gives:
x = 2/3 * -32
x = -64/3
