Question

20. Solve the system. 3x + y= -6 6.2 + 5y = 6

Answer 1

Answer: x = —1.9867 and y = —0.0399

Step-by-step explanation: What we have here is a pair of simultaneous equations which are;

3x + y = —6 ———(1)

6.2 + 5y = 6 ———(2)

From equation (1), we shall make y the subject of the equation. So, let

y = —6 —3x

Substitute for the value of y into equation (2)

6.2 + 5(—6 —3x) = 6

6.2 —30 —15x = 6

Collecting like terms we now have

6.2 —30 —6 = 15x

Remember that when a negative value crosses to the other side of an equation it becomes positive and vice versa

—29.8 = 15x

Divide both sides of the equation by 15

x = —1.9867

We can now substitute for the value of x into equation (1)

3x + y = —6

3(—1.9867) + y = —6

—5.9601 + y = —6

By collecting like terms we now have

y = —6 + 5.9601

y = —0.0399.

Hence x = —1.9867 and y = —0.0399

Answer 2

The first one 3x + y= -6

First 3x + y= -6
-3 -3x
——. ——
y= -3x-6

Second 6.2 + 5y = 6
-6.2. -6.2
———- ———
5y= -0.2
—— ——-
5. 5

y = -0.2/5 or -0.04 as decimal