Question

1). { - 5х + у = 15 5х - 2у = - 35

Answer 1

Ответ:

x = 1, y = 20

Объяснение:

$\left \{ {{-5x+y=15} \atop {5x-2y=-35}} \right. \\\left \{ {{y=15+5x} \atop {5x-2(15+5x)=-35}} \right. \\\left \{ {{y=15+5x} \atop {5x-30-10x=-35}} \right. \\5x-30-10x=-35\\-30-5x=-35\\-5x=-35+30\\-5x=-5\\x=1 = > y=20$

Answer 2

Ответ:

{ - 5х + у = 15

{ 5х - 2у = - 35

Додамо 1 рівняння до 2 рівняння

буде

-у = - 20

у = -20 : (-1)

у = 20

Значення у підставляємо в любе рівняння, наприклад друге

5х - 2у = - 35

5х - 2•20= - 35

5х - 40 = - 35

5х = - 35 + 40

5х = 5

х = 5 : 5

х = 1

Відповідь ( 1 ; 20 ).

Answer 3

To solve the system of equations:

-5x + y = 15 ...(Equation 1) 5x - 2y = -35 ...(Equation 2)

We can use the method of elimination or substitution. Let's use the method of elimination.

To eliminate x, we can add Equation 1 and Equation 2:

(-5x + y) + (5x - 2y) = 15 + (-35)

Simplifying the equation:

-5x + 5x + y - 2y = -20

Combining like terms:

-y = -20

Now, we can solve for y by multiplying both sides of the equation by -1:

y = 20

Now that we have the value of y, we can substitute it back into one of the original equations to solve for x. Let's substitute it into Equation 1:

-5x + y = 15

-5x + 20 = 15

Subtracting 20 from both sides:

-5x = 15 - 20

-5x = -5

Dividing both sides by -5:

x = 1

Therefore, the solution to the system of equations is x = 1 and y = 20.