Katie went shopping with her friends erin. katie bought 3 shirts and 2 pairs of pants for $80. erin bought 3 shirts and 4 pairs of pants for $116. how much did one shirt cost? how much did one pair of pants cost?

Step-by-step explanation:

shirt = x, pants: y

Katie equation: 3x + 2y = 80, Erin equation: 3x + 4y = 116  

3x + 2y = 80

3x = 80 - 2y

x = 80/3 - 2y/3

3(80/3 - 2y/3) + 4y = 116

80 - 2y + 4y = 116

80 + 2y + 116

2y = 36

y = 18, pants cost $18

3x + 4(18) = 116

3x + 72 = 116

3x = 44

x = 14.66... (66 is repeating), shirts cost $14.66

check work:

Katie: 3(14.66) + 2(18) = 79.98 which is roughly 80.

example 2 – simplify: step 1: completely factor both the numerators and denominators of all fractions. step 2: change the division sign to a multiplication sign and flip (or reciprocate) the fraction after the division sign; essential you need to multiply by the reciprocal. step 3 : cancel or reduce the fractions.

x² + 3x + 7 = 0       [ax² + bx + c]

a = 1

b = 3

c = 7

quadratic formula:

    (+/- is this ±)

plug in the numbers into the variables

your answer is a