Question

Please Help!

1. Use substitution to solve the system of equations.
y = 6x
x + 2y = −39

A. (6, −2)(6, −2)
B. (−3, −18)(−3, −18)
C. (5.5, −33)(5.5, −33)
D. (12, 6)

2. Use the elimination method to solve the system of equations.
5x + 2y = 7
−5x + 4y = 5

A.( 3/5, 2)
B. There is no solution.
C. (2,1)
D. There are an infinite number of solutions.

What is the solution of the system? (This question can have more then one answer.)
Use either the substitution method or the elimination method.
y = 4x − 9
y = x − 3

(1, −2)
(3, 0)
(2, −1)
There is no solution.

Answer 1

whatever he said is right

Explanation:

Answer 2

y = 6x...so sub in 6x for y in the other equation

x + 2y = -39
x + 2(6x) = -39
x + 12x = -39
13x = -39
x = -39/13
x = - 3

y = 6x
y = 6(-3)
y = -18

solution is (-3,-18)
======================
5x + 2y = 7
-5x + 4y = 5
-----------------add
6y = 12
y = 12/6
y = 2

5x + 2y = 7
5x + 2(2) = 7
5x + 4 = 7
5x = 7 - 4
5x = 3
x = 3/5

solution is (3/5,2)
========================
y = 4x - 9
y = x - 3
sub one y in for the other
4x - 9 = x - 3
4x - x = -3 + 9
3x = 6
x = 6/3
x = 2

y = x - 3
y = 2 - 3
y = -1

solution is (2,-1)