Question

if x+y=7/10 and x-y=5/14 then x^2-y^2=?

Answer 1

• x+y=7/10=0.7
• x-y=5/14≈0.3

Add both

• 2x=1
• x=1/2=0.5

Put in first one

• y=0.7-0.5
• y=0.2

Find

• x²+y²
• (0.5)²+(0.2)²
• 0.25+0.04
• 0.29