How do I solve these????

Question

How do I go about solving these questions?

Solve:

Question 1:
4x^2 – 28x + 40 = 0

Question 2:
12y^2 + 35y + 25 = 0

Question 3:
x(x – 2) = 8

Question 4:
45n^2 + 21n = 0

Answer 1

Question 1:
4x^2 – 28x + 40 = 0
1. simplify
2. factor
4(x^2-7x+10)=0
4(x-2)(x-5)
x= 0,2,5

Question 2:
12y^2 + 35y + 25 = 0
1.simplify if possible (looks like it cannot be simplifed..makes life complicated..)
2.factor

this will take trial and error.. and lots of it.. one possible answer is
(12x+__)(x+___)
(3x+___)(4x+___)
(2x+___)(6x+___)
goodluck

Question 3:
x(x – 2) = 8
1.expand the problem
2.set the equation to zero
3.now factor
x^2-2x=8
x^2-2x-8=0
(x-4)(x+2)
x=4,-2

Question 4:
45n^2 + 21n = 0
1.same thing just factor this question will take too much time for me to answer lol.

Answer 2

Question 1:
4x^2 – 28x + 40 = 0
(4x-8)(x- 5)=0
x=2,5
Question 2:
12y^2 + 35y + 25 = 0
(4y+ 5)(3y+ 5)=0
y=-5/4,-5/3
Question 3:
x(x – 2) = 8
x^2-2x-8=0
(x-4)(x+2)=0
x=4,-2
Question 4:
45n^2 + 21n = 0
3n(15n+7)=0
n=0,-7/15

Answer 3

These are all simple, quadratic equations. I'll bet there's a whole chapter (maybe even two) in your math book about them. Try reading it. Here's a hint: Factor a 4 out of the first one to get
x² - 7x + 10 = 0 then
(x - 5)(x - 2) = 0 and
x=5 or x=7.

Doug