-10/40 = y / -5
cross multiply
(40)(y) = (-5)(-10)
40y = 50
y = 50/40
y = 5/4 <===
STEP 1:
find the sales tax (decimal form)
x= sales tax
Cost + (Cost * Sales Tax)= Total
plug in known numbers
$9.40 + ($9.40 * x)= $9.87
9.40 + 9.40x= 9.87
subtract 9.40 from both sides
9.40x= 0.47
divide both sides by 9.40
x= 0.47/9.40
x= 0.05 sales tax decimal form
STEP 2:
find sales tax percentage
= 0.05 * 100
or move decimal to the right two decimal places
= 5% sales tax percent form
ANSWER: The sales tax is 5% (or 0.05 in decimal form)
Hope this helps! :)
Let's say that y is the unknown
180=2x+3+5x+1+y
180=7x+4+y
180-7x-4=y
176-7x=y=third angle
