# Algebra

posted by on .

How do you solve and graph these equations?

y = 4x + 5
x - 2y = 4

• Algebra - ,

y = 4 x + 5, through (0,5) slope 4

2y = x - 4
y = (1/2) x - 2 , through(0,-2) slope (1/2)

now subtract second from first to get rid of y
0 = 3.5 x +7
x = -2
then y = -8+5 = -3
so they cross at (-2,-3)
check
y = 4x + 5
-3=4(-2)+5??
-3=-8+5 yes
x - 2y = 4
-2 -2(-3) =4 ??
-2 +6 = 4 sure enough
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