Answer:
See explanation
Step-by-step explanation:
Given
[tex](8x+12y)^2+(6x+9y)^2=(10x+15y)^2[/tex]
Note
[tex](8x+12y)^2=(4(2x+3y))^2=16(2x+3y)^2\\ \\(6x+9y)^2=(3(2x+3y))^2=9(2x+3y)^2\\ \\(10x+15y)^2=(5(2x+3y))^2=25(2x+3y)^2[/tex]
Since
[tex]16(2x+3y)^2+9(2x+3y)^2=(2x+3y)^2(16+9)=25(2x+3y)^2,[/tex]
this is an identity