On the 21st day, he sprints 205 yards.
Is that what you meant for the problem
or do u want to know how many yards he sprinted total for the 21 days
If it is,
he sprinted a total of 3390 yards
Slope = (-2 - 10)/(12 + 6) = -12/18 = -2/3
y = mx + b
10 = -2/3(-6) + b
10 = 4 + b
b =6
equation
y = -2/3x + 6
<span>x-intercept when y = 0
</span>-2/3x + 6 = 0
-2/3x = -6
x = 6 (3/2)
x = 9
answer is <span>d.9</span>
Use ax^2 + bx + c = 0
ac = -8
b = 2
The factors are 4 and -2.
Plug them into the equation:
x^2 + 4x - 2x - 8
Then factorise it:
x ( x + 4) - 2 (x + 4)
so m = 4
(x + 4)^2
(3x - 4)(2x^2 + 2x - 1) = 3x(2x^2 + 2x - 1) - 4(2x^2 + 2x - 1) = (6x^3 + 6x^2 - 3x) - (8x^2 + 8x - 4) = 6x^3 + 6x^2 - 3x - 8x^2 - 8x + 4 = 6x^3 - 2x^2 - 11x + 4