Answer:
x=4
Step-by-step explanation:
In order to solve for x, we must isolate x on one side of the equation.
x+3x+5=21
First, combine like terms. x and 3x are both terms with variables, and can be combined.
(x+3x) + 5=21
4x + 5=21
5 is being added to 4x. The inverse of addition is subtraction. Subtract 5 from both sides of the equation.
4x+5-5= 21-5
4x= 16
x is being multiplied by 4. The inverse of multiplication is division. Divide both sides by 4.
4x/4=16/4
x= 16/4
x=4
Let's check our solution. Plug 4 in for x and solve.
x+3x+5=21
4+3(4)+5=21
4+12+5=21
16+5=21
21=21
This solution checks out, so we know our answer is correct.
x is equal to 4, x=4.
To find the x-int., let y = 0 and solve for x: 13x = 6, so x = 6/13: (6/13, 0)
To find the y-int., let x =0 and read off the y-int: (0, -6)
- 9 + 12 = 3 or +3
Hopes this helps! =)
Answer:
Step-by-step explanation:
Since the slope is -5 is either C or D. Let's replace 
in either to see what we get.
C: 
Nope.
D: 
Good!
