4(2x + 10)=0
8x + 40 = 0
8x = -40
x = -5
I like the substitution method. Which is when you make one equation equal only x or y and plug it into the other equation)
There is also the graphing method. If you graphed it, it might not be quite as accurate (at least on hand, on computer you would be pretty exact)
Then there is the elimination method. You multiply one of the equations by a coefficient so that you can eliminate x or y from the equation.
Let's use the slope intercept form of a line which is:
y=mx+b where m=slope and b=y-intercept.
Mathematically m=(y2-y1)/(x2-x1) and the y-intercept is just the value of y when x is equal to zero, where the line intercepts the y axis...
First you want to find the slope by finding two clearly identifiable points on the graph...I'll pick (4,4) and (0,1), now we can calculate the slope or "m"...
m=(4-1)/(4-0)=3/4 so now we can say our line is:
y=0.75x+b, using point (4,4) we can now solve for b.
4=0.75(4)+b
4=3+b
b=1 so the line is"
y=0.75x+1