Let's solve this problem step by step.
1. First of all we have this equation:
[tex]3(x + 4y) + 5(2x - y)[/tex]
2. Let's apply distributive property:
[tex]3x+12y + 10x - 5y[/tex]
3. Let's order this expression according to the variables:
[tex]3x + 10x + 12y-5y[/tex]
4. Let's sum equal terms:
[tex]13x + 7y[/tex]
