Question 760544
Two angles are supplements when they add up to 180

Equation 1: {{{A + B = 180}}}
Equation 2: {{{A = 4B - 5}}}
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Plug (4B - 5) into equation 1 for A
Equation 1: {{{A + B = 180}}}
{{{(4B - 5) + B = 180}}}
Combine like terms
{{{5B - 5 = 180}}}
Add 5 to both sides
{{{5B = 185}}}
Divide both sides by 5
{{{highlight(B = 37)}}}
Now plug 37 into equation 2 for B
Equation 2: {{{A = 4B - 5}}}
{{{A = 4*(37) - 5}}}
{{{highlight_green(A = 143)}}}