Solve {c}{y=72000(t)^2-1800*t+20}{t=1/80}

$$\left. \begin{array} { c } { y = 72000 ( t ) ^ { 2 } - 1800 \cdot t + 20 } \\ { t = \frac { 1 } { 80 } } \end{array} \right.$$

Solve for y, t

$$y = \frac{35}{4} = 8\frac{3}{4} = 8.75$$

$$t=\frac{1}{80}=0.0125$$

Solution Steps

Consider the first equation. Insert the known values of variables into the equation.

$$y=72000\times \left(\frac{1}{80}\right)^{2}-1800\times \frac{1}{80}+20$$

Calculate \frac{1}{80} to the power of 2 and get \frac{1}{6400}.

$$y=72000\times \frac{1}{6400}-1800\times \frac{1}{80}+20$$

Multiply 72000 and \frac{1}{6400} to get \frac{45}{4}.

$$y=\frac{45}{4}-1800\times \frac{1}{80}+20$$

Multiply -1800 and \frac{1}{80} to get -\frac{45}{2}.

$$y=\frac{45}{4}-\frac{45}{2}+20$$

Subtract \frac{45}{2} from \frac{45}{4} to get -\frac{45}{4}.

$$y=-\frac{45}{4}+20$$

Add -\frac{45}{4} and 20 to get \frac{35}{4}.

$$y=\frac{35}{4}$$

The system is now solved.

$$y=\frac{35}{4} t=\frac{1}{80}$$