Question

-3x+5y=-9 and 4x+8y=12

Answer 1

Let's solve your system by substitution.

−3x+5y=−9;4x+8y=12

Step: Solve−3x+5y=−9for x:

−3x+5y=−9

−3x+5y+−5y=−9+−5y(Add -5y to both sides)

−3x=−5y−9

−3x

−3 = −5y−9 −3

(Divide both sides by -3)

x=

5

3

y+3

Step: Substitute

5

3

y+3forxin4x+8y=12:

4x+8y=12

4(

5

3

y+3)+8y=12

44

3

y+12=12(Simplify both sides of the equation)

44

3

y+12+−12=12+−12(Add -12 to both sides)

44

3

y=0

44

3

y

44

3

=

0

44

3

(Divide both sides by 44/3)

y=0

Step:

3 y+3:

x= 5

3 y+3

x= 5

3 (0)+3

x=3(Simplify both sides of the equation)

Answer:

x=3 and y=0

Answer 2

-3x + 5y = -9

4x + 8y = 12

Simplify the second,

x + 2y = 3

Times three,

3x + 6y = 9

Add to the first equation,

11y = 0

y = 0

-3x + 5(0) = -9

x = 3

Answer: x=3, y=0