Question

Question 1:

Solve this system of equations using any method.

4x – y = 5
3x + y = 16

a. (3, 5)

b. (4, 11)

c. (4, 4)

d. (3, 7)

Question 2:

Solve the following system of equations.

d + e = 6
d – e = 4

a. no solution

b. (5, 1)

c. (3, –1)

d. infinite number of solutions

Question 3:

Solve the following system of equations by linear combination:

4x + 3y = 12
y = x – 10

a. (3, –7)

b. (6, –4)

c. (–7, 3)

d. (–4, 6)

Answer 1

Question 1: d. (3, 7)

Question 2: b. (5, 1)

Question 3: b. (6, –4)

Explanation:

Question 1:

Solve this system of equations using any method.

4x – y = 5

3x + y = 16

Add the equations.

7x = 21

x = 3

4(3) - y = 5

-y = -7

y = 7

d. (3, 7)

Question 2:

Solve the following system of equations.

d + e = 6

d – e = 4

Add the equations.

2d = 10

d = 5

5 + e = 6

e = 1

b. (5, 1)

Question 3:

Solve the following system of equations by linear combination:

4x + 3y = 12

y = x – 10

4x + 3y = 12

-x + y = -10

Multiply the second equation by 4 and add to the first equation.

4x + 3y = 12

(+) -4x + 4y = -40

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

7y = -28

y = -4

-4 = x - 10

x = 6

b. (6, –4)