Find the approximate solution of the given system of equations.

8x + 9y = 9
3x – 5y = 20

a.
3.36, –1.99
c.
0, –1.99
b.
–1.11, 2.79
d.
3.36, 2.79

Question

Find the approximate solution of the given system of equations.
  
8x + 9y = 9
3x – 5y = 20
 
a.
3.36, –1.99
c.
0, –1.99
b.
–1.11, 2.79
d.
3.36, 2.79

anonymous · Answer

8x+9y=9
3x-5y=20

The first step is to multiply the first equation by 5 and the second by 9
5(8x+9y=9)
9(3x-5y=20)

Use the distributive property and then set them up like this and solve
  40x+45y=45
+
  27x-45y=180
---------------
  67x=225

67x/67=225/67

x= 3.36

Now plug x into either equation and solve. I chose the first as it is the easiest.

8(3.36)+9y=9
 
26.88 +9y=9
-26.88        -26.88
-------------------
9y/9=17.88/9

y= -1.99

So the answer is A