Question 152454
 factor by grouping: 

{{{8x^2+18x-35}}}
<pre><font size = 4 color = "indigo"><b>
Multiply the {{{8}}} by the {{{-35}}} and get {{{-280}}}
Write down all the pairs of factors of its absolute value,
{{{280}}}:

{{{280*1}}}
{{{140*2}}}
{{{70*4}}}
{{{56*5}}}
{{{40*7}}}
{{{35*8}}}
{{{28*10}}}
{{{20*14}}}

Now since the LAST SIGN in {{{8x^2+18x-35}}}
is MINUS, we SUBTRACT the two 
factors in absolute value:

<font size = 1 color = "red"></b>[Note: If the last term had been PLUS, we 
would have ADDED the two factors in 
absolute value.]</font><b>

{{{280-1=279}}}
{{{140-2=138}}}
{{{70-4-66}}}
{{{56-5=51}}}
{{{40-7=33}}}
{{{35-8=27}}}
{{{28-10=18}}}
{{{20-14=6}}}

Now we look at the middle term of {{{8x^2+18x-35}}},
which is {{{18}}} and we look at the 
list of differences and find the
absolute value of {{{18}}} in the next to
last difference, {{{28-10=18}}}.

So we substitute {{{28-10}}} for the 18:

{{{8x^2+18x-35}}}
{{{8x^2+(28-10)x-35}}}

Now we remove the parentheses by distributing:

{{{8x^2+28x-10x-35}}}

Factor {{{4x}}} out of the first two terms
Factor {{{-5}}} out of the last two terms:

{{{4x*(2x+7)-5(2x+7)}}}

Now factor out {{{(2x+7)}}}

{{{(2x+7)(4x-5)}}}

Edwin</pre>