Gr.10 Math!!!! urgent
posted by nini on .
Factor by Grouping. PLEASE SHOW ME THE STEPS!
1.) 8a^2+12ab3b^22ab
2.) x^2+5x+7x+35

2) first rearrang terms to solve
x^2+5x+7x+35
x^2+12x+35
now what two numbers added together make 12 and multiplied make 30? those are your factors to go in the parentheses. Like this:
x^2+12x+35
(x+?)(x+?) this is the answer then. 
thnkss, 1.)??

The first one works like this:
8a^2+12ab3b^22ab
take the first two terms and notice the common multiple of 4 and a. they become
4a(2a+3b)
Now take the last two terms and notice the common multiple of b. they become:
b(2a+3b)
Now see the common factor in the parentheses? (2a+3b)
This comes out in front to become:
(2a+3b)(4ab)
Multiply together to check your answer and you will see it is correct. 
Did that make sense? were you able to solve #1 and understand #2?

for 1.) what formula are u using though?

no set formula. Just remember in problems with more than one variable first factor the first two terms and then the second two terms and look for a common factor(s) which will usually appear in the parentheses or outside. Then multiply this by the remaining terms to get your answer. Always multiply back to out to check your work.
try this problem to see if you understand:
4a^2+2abb^22ab