The expression is: 5x + 6y - 3
<span>solution of a system of linear equations</span>
Step-by-step explanation:
By binomial theorem,
T(r+1) = nCr * a^(r+1) * b^r
Term 4 = 7C3 * (2x)^4 * (-5y)^3 = 35 * (16x^4) * (-125y^3) = -70000x^4y^3.
At 40 seconds I got 23,277 feet so yes it was ever 60 feet