how do you expand, (5x+10)(x+1)?

(5x+10)(x+1)= 5x(x+1)+10(x+1) = 5x^2 + 15x + 10

Monica, are you paying attention in class ? Does the term "FOIL' mean anything to you ?

These binomials can be multiplied using distribution.

(5x + 10)(x + 1) = 5x(x + 1) + 10(x + 1) = 5x^2 + 5x + 10x + 10 = 5x^2 + 15x + 10

QED

(5x + 10)(x + 1)
= 5x(x) + 5x(1) + 10(x) + 10(1)
= 5x^2 + 5x + 10x + 10
= 5x^2 + 15x + 10

Two main methods: a) FOIL (first, outer, inner, last) where you multiply the first terms together, plus the outer terms together....

b) My personal favorite (more useful for larger functions): First times first, first times second... until you run out things in the second bracket, then second times first,second times second, until you run out of stuff in the second bracket and keep repeating until you run out of terms in the first bracket.

For practice try doing both ways. If both ways are the same and they're correct well done, if they're the same but wrong, ask your teacher for help, if they're different and one is correct, you may find that method easier but brush up on the other just in case.

admittedly i did this the awkward way,
i naturally choose one of the brackets then separately multiply the numbers by the bracket, that sounds like BS bt here :) ;
5x(x+1) = 5x(squared) + 5x
10(x+1) = 10x + 10
collect all the like terms
so you have 5x(squared) + 15x +10

5x times x = 5x^2
5x times 1 = 5x
10 times x = 10x
10 times 1 = 10

So....

5x^2 + 5x + 10x + 10 ............ 5x^2+15x+10 is the answer.

5x^2 + 5x + 10x+10

Multiply 5x with X on the second parenthesis and 5x with 1 on the second parenthesis and then x with 10 in the first parenthesis and 1 with 10 in the first parenthesis.

it helps if you draw arrows to what your going to multiply them to