Question

Do on substitution and show work so I can learn for later. please.​

Answer 1

x - 4y = 15

-x          -x  (subtract x on both sides)

-4y = 15 -x

----    -------- (divide by -4 on both sides)

-4      -4

y = -3.75 - 1/4x (change to slope-intercept form which will be y = -1/4x -3.75)

substitute that equation for y on the other equation so you will get

x - 4(-1/4x - 3.75) = 15

x + 1x + 15 = 15 (use distributive property)

2x + 15 = 15 (combine like terms)

2x = 0 (subtract 15 on both sides)

x = 0 (divide both sides by 2)

substitute for x on any equation (Im going to be using x - 4y = 15)

0 - 4y = 15

-4y = 15 (add 0 to both sides)

y = -3.75 (divide both sides by -4)

Point of intersection is (0, -3.75)