Question

What is the x-value that solves the system 4x-y=21 and y=3x-7

Answer 1

Answer: x=14 is right answer

4x-y=21 =

Slope = 4

x-intercept = 21/4 = 5.25000

y-intercept = 21/-1 = -21.00000

y=3x-7 =

Slope = 6.000/2.000 = 3.000

x-intercept = 7/3 = 2.33333

y-intercept = -7/1 = -7.00000

Explanation:

Step 1 :

Equation of a Straight Line

Graph of a Straight Line

Calculate the Y-Intercept

Calculate the X-Intercept

Calculate the Slope

Hope this helps.

Answer 2

x=14

Explanation:

4x-y=21

y=3x-7

Substitute the second equation in for y in the first

4x - (3x-7) = 21

Distribute the minus sign

4x -3x +7 = 21

x +7 = 21

Subtract 7 from each side

x+7-7=21-7

x=14