Question

4(x + y) - 8y = -4,7(y +1) - (y + 3) = 19;​

Answer 1

4х-4у=-4
4х=-4+4у
х=-1+у


7у+7-у-3=19
6у+4=19
6у=19-4
6у=15
у=15:6
у=2,5

Answer 2

To solve the system of linear equations, we'll work through each equation step by step.

Let's start with the first equation: $4(x + y) - 8y = -4$.

1. Distribute the 4: $4x + 4y - 8y = -4$

2. Combine like terms: $4x - 4y = -4$

Now, let's move on to the second equation: $7(y + 1) - (y + 3) = 19$.

1. Distribute the 7 and the negative sign inside the parentheses: $7y + 7 - y - 3 = 19$

2. Combine like terms: $6y + 4 = 19$

Now, we have a system of two equations:

1. $4x - 4y = -4$
2. $6y + 4 = 19$

Let's solve for $y$ in the second equation:

$6y + 4 = 19$

Subtract 4 from both sides:

$6y = 15$

Now, divide both sides by 6 to solve for $y$:

$y = \frac{15}{6} = \frac{5}{2}$

Now that we have $y$, let's substitute this value into the first equation to solve for $x$:

$4x - 4\left(\frac{5}{2}\right) = -4$

Now, solve for $x$:

$4x - 10 = -4$

Add 10 to both sides:

$4x = 6$

Now, divide both sides by 4 to solve for $x$:

$x = \frac{6}{4} = \frac{3}{2}$

So the solutions for the system of equations are: $x = \frac{3}{2}$ and $y = \frac{5}{2}$.