I need help on these problems. There over solving equations by factoring.

1. 4x^2=9

2. M^2-36=16M

3. R^2+9=10r

4. 6s^2=17s-12

3 answers

set everything to zero, then you can factor.

#4
6s^2-17s+12 = 0
You know the factors will look like
(6x-?)(x-?) or (3x-?)(2x-?)
So, since -17 is fairly large, we will probably have the first
(6s-3)(s-4) gives -27s too big
(6s-4)(s-3) gives -22s still too big
(6s-6)(s-2) gives -18s close, but no cigar
(3s-4)(2s-3) gives -17s YES!

Do the others the same way. #1 involves a difference of squares, so it's easy.
Would #4 be s=1 and s=2?
well, no.
If the product of some numbers is zero, then one of the numbers must be zero. We have

(3s-4)(2s-3) = 0
So, we must have either
3s-4 = 0
or 2s-3 = 0

So, s = 4/3 or 3/2

Had you tried your guesses in the original equation, you would have seen they did not satisfy it.