30% = 0.3.
0.3*80 = 24, so we know that 30% of 80 is 24.
80 - 24 = 56, so after the sale, the price for a pair of jeans is $56.
10% = 0.1
0.1*56 = 5.6, so with the coupon, we get $5.60 off.
56 - 5.60 = 50.40
The jeans cost $50.40 after the sale and the coupon.
X^2 - 13 x = -36
add 36 to both sides
x^2 - 13x +36 = 0
figure out the factor
(x-4)(x-9) = 0
so (x-4) or (x-9) equals 0
so solution is
x-4=0 add 4 to both sides and get x = 4
x-9=0 add 9 to both sides and get x=9
x={ 4, 9}
48 ounces give you 3 pounds.