Explanation
The method of substitution consists of 3 steps:
0. Solve one equation for one of the variables.
,
1. Substitute the expression into the other equation and solve.
,
2. Resubstitute the value into the original equation to find the corresponding variable.
In this case, we have the system of equations:
[tex]\begin{cases}y=-5x^2+2x+7\Rightarrow\text{ Equation 1} \\ y={-3x+4\Rightarrow\text{ Equation 2}}\end{cases}[/tex]
As we can see, the first step is done.
Then, for the next step, we can substitute the value of y from Equation 1 in Equation 2.
[tex]\begin{gathered} \begin{equation*} y=-3x+4 \end{equation*} \\ -5x^2+2x+7=-3x+4 \end{gathered}[/tex]Answer
The first step in solving the given system of equations by substitution is:
[tex]-5x^{2}+2x+7=-3x+4[/tex]
