Solve the system by substitution. {:[y=2x],[y=9x+21]:} (◻,◻)

Substitute y into second equation: Substitute y from the first equation into the second equation. y = 2x (first equation) y = 9x + 21 (second equation) Replace y in the second equation with 2x from the first equation. 2x = 9x + 21Solve for x: Solve for x. Subtract 9x from both sides of the equation to isolate x. 2x - 9x = 9x + 21 - 9x -7x = 21Divide to find x: Divide both sides by -7 to find the value of x. -7x / -7 = 21 / -7 x = -3Substitute x into first equation: Substitute x back into the first equation to find y. y = 2x y = 2(-3) y = -6Write solution as ordered pair: Write the solution as an ordered pair (x, y). The solution is (-3, -6).

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Solve the system by substitution.

{:[y=2x],[y=9x+21]:}

(◻,◻)

Solve the system by substitution. $\newline$ $\begin{array}{l} y=2 x \\ y=9 x+21 \end{array}$ $\newline$ $(\square, \square)$

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Algebra 2

Solve a system of equations in three variables using substitution

Full solution

Q. Solve the system by substitution.

\newline

\begin{array}{l} y=2 x \\ y=9 x+21 \end{array}

\newline

(\square, \square)

Substitute $y$ into second equation: Substitute $y$ from the first equation into the second equation. $\newline$ $y = 2x$ (first equation) $\newline$ $y = 9x + 21$ (second equation) $\newline$ Replace $y$ in the second equation with $2x$ from the first equation. $\newline$ $2x = 9x + 21$
Solve for x: Solve for x. $\newline$ Subtract $9x$ from both sides of the equation to isolate $x$ . $\newline$ $2x - 9x = 9x + 21 - 9x$ $\newline$ $-7x = 21$
Divide to find x: Divide both sides by $-7$ to find the value of x. $\newline$ $-7x / -7 = 21 / -7$ $\newline$ $x = -3$
Substitute $x$ into first equation: Substitute $x$ back into the first equation to find $y$ . $y = 2x$ $y = 2(-3)$ $y = -6$
Write solution as ordered pair: Write the solution as an ordered pair $(x, y)$ . $\newline$ The solution is $(-3, -6)$ .