Answer:
1 plain pizza costs $10.50 and 1 pepperoni pizza costs $12.50
Step-by-step explanation:
Jack: 3x+2y= 58.5
Jill: 2x+4y=67
a) Multiply both equations so that one of the coefficients (number before the letter) are equal:
6x+4y=117
6x+12y=201
b) We can now easily subtract them to get:
(subtracted 6x) 4y=117 12y=201 (12y-4y and 201-117 next) 8y=84
c) Now we can divide 84 by 8 to get y=10.5, so now we can substitute it into any of the equations:
2x+(4*10.5)=67 --> 2x+42=67 -(subtract 42 from both sides)-> 2x=25 -(divide both side by 2)-> x=12.5.
d) To check if it works: 2(12.5)+4(10.5)=67 25+42=67 so it's correct.
