Answer:
Second option: 81y^4 - 16x^2, the difference of squares
Step-by-step explanation:
(9y^2-4x)(9y^2+4x) is a special product named difference of squares, then we can apply this formula:
(a-b)(a+b)=a^2-b^2, with a=9y^2 and b=4x, then:
(9y^2-4x)(9y^2+4x)=(9y^2)^2 - (4x)^2
(9y^2-4x)(9y^2+4x)=(9)^2 (y^2)^2 - (4)^2 (x)^2
(9y^2-4x)(9y^2+4x)=81y^(2*2) - 16x^2
(9y^2-4x)(9y^2+4x)=81y^4 - 16x^2
6x - 5y = 5
3x + 5y = 4
----------------add
9x = 9
x = 9/9
x = 1 <===
Someone is writing the answer so ill just give you this tip for whenever.
A negitive times a negitive is positive
a negative times a positive is negitive
and a positive times a positive is positive (just had to add it to be complete)
Answer:
(2x+2)
Step-by-step explanation:
1) move the 10 over
So it becomes
3/4b = 10
2) multiply everything by 4 to get rid of the denominator
2b = 40
3) divide both sides by 2
b = 20
