Change the variables so that the expression has the form x^2+bx+c.
4(y-3)(4y+5)
Practice makes perfect
We want to factor the given expression.
(4y-5)^2+3(4y-5)-70
It seems hard to factor it. Let's change the variables so that the expression has the form x^2+ax+b. Let u= 4y-5.
( 4y-5)^2+3( 4y-5)-70
⇕
u^2+3 u-70
We can factor this expression easily.
Now, let's put (4y-5) back into this factored expression.
(u-7)(u+10)
⇕
( 4y-5-7)( 4y-5+10)
After the simplification, we are done!
(4y-12)(4y+5)
We can also factor out the greatest common factor.
4(y-3)(4y+5)
