Question

Solve the simultaneous equations 3x + y = 25 2x – y = 10

Answer 1

Answer:

x=7 and y=4

Step-by-step explanation:

I will use the elimination method:

Since the co-efficient of both y's are the same number but different signs we add the 2 equations to eliminate the y:

3x + y =25
+     +     +

2x - y = 10

Simplify:

5x=35

Divide both sides by 5:

5x÷5=35÷5

Simplify:

x=7

Substitute this into either equation 1 or 2 ( I chose 1):

3(7) + y = 25

21 + y = 25

Subtract 21 from both sides and simplify to get y:

21+y-21=25-21

y=4

Therefore x=7 and y=4