Step-by-step explanation:
set notebooks as x, set pens as y
1. 5x + 7y = 11
2. 4x + 2y = 7
1. times by 2
10x + 14y = 22
2. times by 7
28x + 14y = 49
2. minus 1.
18x = 27
x = 1.5
sub 1.5 into 2.
4(1.5) +2y = 7
6+2y = 7
2y = 1
y = 0.5
Therefore, x = 1.5, y = 0.5
Answer:
(x+a) (x+b)=x(x+b)+a(x+b)=x²+bx+ax+ab=x²+x(a+b)+ab
You are taking away 4 each time
25 - 4 = 21
21 - 4 = 17
17 - 4 = 13
13 - 4 = 9
