Question

А) (а+b=42 (2a+18b=420

Answer 1

Ответ:

Пошаговое объясна) a+b=42

2a+18b=420

Выразим а из первого уравнения :

a=42-b

2a+18b=420

Подставим значение а во второе уравнение:

а=42-b

2*(42-b)+18b=420

a=42-b

84-2b+18b=420

a=42-b

b=21

Подставим значение b в выражение с а

a=42-21

b=21

a=21

b=21ение:

Answer 2

To solve this system of equations for 'a' and 'b,' you can use the method of substitution or elimination. Let's use the elimination method:

Given:

1. a + b = 42
2. 2a + 18b = 420

First, let's simplify equation 1 by multiplying it by 2 to match the coefficients of 'a' in both equations:

1. 2(a + b) = 2(42) 2a + 2b = 84

Now, we have the system of equations:

1. 2a + 2b = 84
2. 2a + 18b = 420

Next, we can subtract equation 1 from equation 2 to eliminate 'a':

(2a + 18b) - (2a + 2b) = 420 - 84

This simplifies to:

16b = 336

Now, divide both sides by 16 to find 'b':

b = 336 / 16 b = 21

Now that we have found 'b,' we can substitute it back into equation 1 to solve for 'a':

a + 21 = 42

Subtract 21 from both sides:

a = 42 - 21 a = 21

So, the solution to the system of equations is:

a = 21 b = 21

Therefore, the values of 'a' and 'b' that satisfy both equations are a = 21 and b = 21.