## anonymous 3 years ago plz help Mary thought of two numbers. She doubled her first number and trebled the second, added these two together and got 5. Then she multiplied her first number by four and added this to her second number. This time she got a result of 15. Find the first two numbers.

1. anonymous

Okay, let's see if this works :P We'll call the first number x and the second y. 2x+3y=5 Then... 4x+y=15 To solve these you could put them onto a graph, by rewriting them. 3y=5-2x and y=15-4x Hopefully this should work! You should get 2 results for numbers on the x axis, which are your answers...

2. anonymous

okay thanks

3. anonymous

thats right!

4. anonymous

$\text{Take it like this ..}$$\large\color{blue}{2x+3y=5}$$\large\color{green}{4x+y=15}$$\text{Now solve for x and y using substitution or any other method...}$

5. anonymous

are the answers 4 and -1

6. anonymous

$\text{You could do it like this..}$$4x+y=15$$x=\frac{15-y}{4}$Now substitute this..$3y=5-2x$$3y=5-2(\frac{15-y}{4})$$3y=5-(\frac{15-y}{2})$$6y=10-15+y$$5y=-5$$y=-1$$\text{So to find x}$$x=\frac{15-y}{4}$$x=\frac{15-(-1)}{4}$$x=\frac{16}{4}$$x=4$

7. anonymous

YES