Solve by Addition/Elimination 3x+4y=2 , 6x+8y=4

$3 x + 4 y = 2$ , $6 x + 8 y = 4$

Step 1

Multiply each equation by the value that makes the coefficients of $x$ opposite.

$(- 2) \cdot (3 x + 4 y) = (- 2) (2)$

$6 x + 8 y = 4$

Step 2

Simplify.

Simplify the left side.

Simplify $(- 2) \cdot (3 x + 4 y)$ .

Apply the distributive property.

$- 2 (3 x) - 2 (4 y) = (- 2) (2)$

$6 x + 8 y = 4$

Multiply.

Multiply $3$ by $- 2$ .

$- 6 x - 2 (4 y) = (- 2) (2)$

$6 x + 8 y = 4$

Multiply $4$ by $- 2$ .

$- 6 x - 8 y = (- 2) (2)$

$6 x + 8 y = 4$

$- 6 x - 8 y = (- 2) (2)$

$6 x + 8 y = 4$

$- 6 x - 8 y = (- 2) (2)$

$6 x + 8 y = 4$

$- 6 x - 8 y = (- 2) (2)$

$6 x + 8 y = 4$

Simplify the right side.

Multiply $- 2$ by $2$ .

$- 6 x - 8 y = - 4$

$6 x + 8 y = 4$

$- 6 x - 8 y = - 4$

$6 x + 8 y = 4$

$- 6 x - 8 y = - 4$

$6 x + 8 y = 4$

Step 3

Add the two equations together to eliminate $x$ from the system.

	$-$	$6$	$x$	$-$	$8$	$y$	$=$	$-$	$4$
$+$		$6$	$x$	$+$	$8$	$y$	$=$		$4$
						$0$	$=$		$0$

Step 4

Since $0 = 0$ , the equations intersect at an infinite number of points.

Infinite number of solutions

Step 5

Solve one of the equations for $y$ .

Add $6 x$ to both sides of the equation.

$- 8 y = - 4 + 6 x$

Divide each term in $- 8 y = - 4 + 6 x$ by $- 8$ and simplify.

Divide each term in $- 8 y = - 4 + 6 x$ by $- 8$ .

$\frac{- 8 y}{- 8} = \frac{- 4}{- 8} + \frac{6 x}{- 8}$

Simplify the left side.

Cancel the common factor of $- 8$ .

Cancel the common factor.

$\frac{- 8 y}{- 8} = \frac{- 4}{- 8} + \frac{6 x}{- 8}$

Divide $y$ by $1$ .

$y = \frac{- 4}{- 8} + \frac{6 x}{- 8}$

Simplify the right side.

Simplify each term.

Cancel the common factor of $- 4$ and $- 8$ .

Factor $- 4$ out of $- 4$ .

$y = \frac{- 4 (1)}{- 8} + \frac{6 x}{- 8}$

Cancel the common factors.

Factor $- 4$ out of $- 8$ .

$y = \frac{- 4 \cdot 1}{- 4 \cdot 2} + \frac{6 x}{- 8}$

Cancel the common factor.

$y = \frac{- 4 \cdot 1}{- 4 \cdot 2} + \frac{6 x}{- 8}$

Rewrite the expression.

$y = \frac{1}{2} + \frac{6 x}{- 8}$

Cancel the common factor of $6$ and $- 8$ .

Factor $2$ out of $6 x$ .

$y = \frac{1}{2} + \frac{2 (3 x)}{- 8}$

Cancel the common factors.

Factor $2$ out of $- 8$ .

$y = \frac{1}{2} + \frac{2 (3 x)}{2 (- 4)}$

Cancel the common factor.

$y = \frac{1}{2} + \frac{2 (3 x)}{2 \cdot - 4}$

Rewrite the expression.

$y = \frac{1}{2} + \frac{3 x}{- 4}$

Move the negative in front of the fraction.

$y = \frac{1}{2} - \frac{3 x}{4}$

Step 6

The solution is the set of ordered pairs that make $y = \frac{1}{2} - \frac{3 x}{4}$ true.

$(x, \frac{1}{2} - \frac{3 x}{4})$

Step 7

The result can be shown in multiple forms.

Point Form:

$(x, \frac{1}{2} - \frac{3 x}{4})$

Equation Form:

$x = x, y = \frac{1}{2} - \frac{3 x}{4}$

Step 8

Solve by Addition/Elimination 3x+4y=2 , 6x+8y=4

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