Solve - 4x + 7y = 20; y = 3x + 15; x =; y = | Equatix - Math Solver

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Example

3(r+2s)=2t-4

a⋅(b-2)=3b

3(r+2s)=2t-4

a⋅(b-2)=3b

Question

$$-4x+7y=20; y=3x+15; x=; y=$$

Solve for x, y, z

$z=-5$

Short Steps Using Substitution

Reorder the equations.

$$y=3x+15$$ $$-4x+7y=20$$ $$z=x$$

Substitute $15+3x$ for $y$ in the equation $-4x+7y=20$.

$$-4x+7\left(15+3x\right)=20$$

Solve $-4x+7\left(15+3x\right)=20$ for $x$.

$$x=-5$$

Substitute $-5$ for $x$ in the equation $z=x$.

$$z=-5$$

Substitute $-5$ for $x$ in the equation $y=3x+15$.

$$y=3\left(-5\right)+15$$

Calculate $y$ from $y=3\left(-5\right)+15$.

$$y=0$$

The system is now solved.

$$x=-5$$ $$y=0$$ $$z=-5$$