Question

If 5x – 2y = 7 and xy = 2, find the value of (5x + 2y)²​

Answer 1

Answer:

Given 5x-2y=7,

xy=2

Step-by-step explanation:

(5x+2y)2= (5x)2+(2y)2+2(5x)(2y)

=(5x)2+(2y)2+2(5x)(2y)+2(5x)(2y)-2(5x)(2y)

(subracting adding 2(5x)(2y))

= [(5x)2+(2y)2-2(5x)(2y)]+4(5x)(2y)

=(5x-2y)2+40xy

=7square+ 40*2

=49+80

=129