Verified answer

5b (2a – 4b) + 6(3ab – 4b²)

multiply it out

10ab-20b^2 + 18ab-24b^2

combine terms which are alike such as 10ab and 18ab

28ab-44b^2

take out terms which are common in both phrases

4b (7a - 11b)

To put it more simply than the first answer (though it is correct)

multiply out the brackets

5bx2a= 10ab

5bx-4b= 20b^2

6x3ab=18ab

6x-4b^2=24b^2

now you have

10ab-20b^2 + 18ab - 24b^2

now you gather the like terms

28ab - 44b^2

What answerer two have done is to factorise it, which technically makes it simpler but is not generally what a simplify question is looking for. However, if you think it wants the next step you'd take out the highest common factor of 4b

4b (7a-11b)

Distribute and simplify from there.

5b (2a-4b) = 10ab - 20b^2

6(3ab-4b^2) = 18ab - 24b^2

then you combine like terms (add them in this case)

28ab - 44b^2