Question

I need help on these problems. There over solving equations by factoring. Don't get it at all.

1. (Y+5)(Y-7)=0

2. 2n(n-20)=0

3. (2t-3)(3t-2)=0

4. (2u+7)(3u-1)=0

Answer 1

1. (Y+5)(Y-7)=0
if Y = -5
then you have (-5+5) (something) = 0
or 0 * something = 0
so 0 = 0
so Y = -5 IS A SOLUTION
same deal for Y = 7
(something)( 7 - 7 ) = 0
sure enough y = 7 Is a solution

so I claim in general
if (something ) (a x + b) = 0
then
x = -b/a
IS a solution

for example:
2n(n-20) = 0
( 2n + 0) (something ) = 0
so n = -0/2 = 0 IS A SOLUTION
and
something * ( n -20)= 0
if n = -(-20/1) = +20 then (n-20) = 0
then n = + 20 IS A SOLUTION

t = +3/2 and t = +2/3

u = -7/2 and u = +1/3

Answer 2

1.(Y+5)(Y-7)=0

y+5=0 y-7=0
y=0-5 y=0+7
y=-5 y=7

2. 2n(n-20)=0

2n=0 n-20=0
2n/2=0/2 n=0+20
n=0 n=20


3.(2t-3)(3t-2)=0

2t-3=0 3t-2=0
2t=0+3 3t=0+2
2t=3 3t=2
2t/2=3/2 3t/3=2/3
t=3/2 t=2/3


4.(2u+7)(3u-1)=0

Follow above!