work out M and C: 2y + 6x = -4
Answers (2)
m = slope
c = y-intercept
2y + 6x = -4 ;; minus 6x
2y = - 6x - 4 ;; divide by 2
y = -3x - 2 ;; this is the slope intercept form, which tells you:
m = -3
c = -2
Btw, if you want to know both intercepts (x-axis and y-axis), use the intercept form:
(x / x_0) + (y / y_0) = 1.
y = -3x - 2 ;; plus 3x
3x + y = -2 ;; divide by 3
x + (y / 3) = (-2 / 3) ;; divide by -2/3
( x / (-2/3)) + ( (y/3) / (-2/3)) = 1 ;; divide by multiplying the inverse
( x / (-2/3)) + ( (y/3) * (3/ -2)) = 1
( x / (-2/3)) + ( 3y / (3 * -2)) = 1
( x / (-2/3)) + (y / -2) = 1.
And now you can simply read the x-intercept from the denominator under x, and
the y-intercept from the denominator under y.
That is a linear equation. The only things you can work out are slope, intercept, and plot.
The plot looks like this: www.wolframalpha.com/input/?ab=c&i=plot+2y+%2B+6x+%3D+-4
2y + 6x = -4 This is written in standard form: variables on the left, no fractions, and zero or a constant on the right. The rule is you can do any valid operation on both sides of an equation and it will still be equal. Subtract 2y.
6x = -2y -4 Divide by 6.
x = -y/3 - 2/3 Notice we do not write -1/3y because that is ambiguous. We could write (-1/3)y if we preferred that notation for some reason. Anyway, this is slope-intercept form. Slope is -1/3 and intercept (where the line crosses the y axis) is -2/3.