knuckles111
contestada

30 pts pls help

11. Solve the system of linear equations below. 4x - 3y = 17 5x + 4y = 60 A. x = 2, y = -3 B. x = 5, y = 8 C. x = 8, y = 5 D. x = -8, y = -5

Respuesta :

altavistard

Answer:

(8, 5) (Answer C)

Step-by-step explanation:

Write this system of linear equations in a (vertical) column:

4x - 3y = 17

5x + 4y = 60

Let's eliminate y through addition/subtraction:

Multiply 4x - 3y = 17 by 4, obtaining 16x - 12y = 68, and

multiply 5x + 4y = 60 by 3, obtaining 15x + 12y = 180.  Then we have:

16x - 12y = 68

15x + 12y = 180

----------------------

31x          = 248, and so x = 248/31 = 8.

Now find y.  Substitute 8 for x in 5x + 4y = 60:  5(8) + 4y = 60, or

4y = 60 - 40 = 20.

Thus, y = 20/4, or y = 5.

The solution is (8, 5) (Answer C)

Otras preguntas