Question

5x+y=77x-4y= -16x-5y= -12x-7y= 13 ​

Answer 1

Объяснение:

1) 5х+у=7

7х–4у= –1

• у=7–5х
• 7х-4у= –1

Подставим значение у во второе уравнение:

7х–4у= –1

7х–4(7–5х)= –1

7х–28+20х= –1

27х= –1+28

х=27÷27=1

теперь найдём значение х в первое уравнение:

у=7–5х=7–5×(–1)=7+5=12

Ответ: х=1; х=12

2) 6х–5у= –1

2х–7у=13 |÷2

• 6х–5у= –1
• х–3,5у=6,5

6х–5у= –1

х=3,5у+6,5

6х–5у= –1

6(3,5у+6,5)–5у= –1

21у+39–5у= –1

16у= –1–39

16у= –40

у= –2,5

х=3,5у+6,5=3,5×(–2,5)+6,5= –8,75+6,5= –2,25

Ответ: х= –2,25; у= –2,5

Answer 2

It looks like you've provided a system of four linear equations with two variables (x and y). To solve this system of equations, we can use various methods such as substitution, elimination, or matrix operations. Let's use the elimination method to solve this system.

Here's the system of equations:

1. $5x + y = 7$
2. $7x - 4y = -16$
3. $-5x - y = -12$
4. $-7x - 7y = 13$

Let's start by using equations 1 and 3 to eliminate the variable $y$. We'll add the two equations to cancel out $y$:

$5x + y + (-5x - y) = 7 + (-12)$ $0 = -5$

We have a contradiction, which means that the system of equations is inconsistent and doesn't have a unique solution. Inconsistent systems have no solution because the equations are conflicting and cannot be satisfied simultaneously.

It's possible that there was a mistake in the equations provided or in the transcription. Please double-check the equations and make sure they are accurate. If you have a different set of equations or if you'd like me to assist you with a different method, please provide the correct equations or more information.