Can you Answer These Math problems THEY ARE HARD??!!?

Question

1)X-2y=-25
3x-y=0

2)u-v=0
7u+v=0

3)2a=8
a+b=2
Use The Substitution Method and the Combination Method.(Please Help)

I still don't get 8 and I have a new ones I tryed

m+2n=1
5m=3n=-23

x-y=0
12x-5y=-21
HELP

Answer 1

1: x and y both equal 25
2: u and v both equal o

3: a equals 4, b equals -2

Answer 2

Actually, they really aren't that hard. I'll get you started, but I won't do them for you.

1. Solve the second equation for y (-y= -3x) then just substitute the answer into the first equation and solve for x. Then substitute that answer into the second equation and solve for y. Both answers are whole numbers and one is a negative number.

2. This one is a little harder, but is easy if you remember that any number divided by 0 = 0, any number multiplied by 0 = 0 and any number subtracted from itself = 0. If you solve the first equation for u, you discover that u = v.

3. Solve the first equation for a then substitute that value into the second equation. Both the answers are whole numbers and one is negative.

Math isn't particularly hard if you just remember your rules and approach the problems logically. Take your time and ask your teacher for some help if you need it. You can also buy books that can help you. One of my favorites you might find helpful is Algebra, the Easy Way.

Answer 3

1) from the second equation 3x-y=0 we get 3x = y then substitute into the first for y to get:
x-2(3x)=-25 now solve for x:
x-6x=-25
-5x = -25
x=5

2) From the first equation u-v=0 we get u=v now substitute into the second equation to get:
7u+v=0 7u + (u) = 0
8u=0
u=0 and since u=v then v = 0 also.

3)
2a=8
a=4 now substitute this into equation 2 to get:

(4) + b = 2
b= -2

Answer 4

x-2y=-25
3x-y=0

multiply the second equ with 2 to make it even

x-2y=-25
6x-2y=0
- + -
---------
-5x = -25
x=5

putting x value in equ

5-2y=-25
y=15

u-v=0
u+v=0
2u=0
u=0
v=0


2a=8
a=8/2
a=4
4+b=2
b=-2