7(y + 6)
25x2-49y2 is the difference of two squares and can be factored as:- (5x-7y)(5x+7y)
It is the factored version of: 14y^2 -13y+3
4(1 - 4x + 7y)
35
The LCM of 6 and 7 is 42.
7y-42=28 ==> 7y=42+28 => y=70/7. => 10
42 divided by 7 is 6. 7y = 42 Divide both sides by 7. y = 6.
Substitute the values of x and y in 10x + 7y, thus: 10x + 7y = 10*9 + 7*6 = 90 + 42 = 132
As a product of its prime factors: 2*3*7 = 42
y2 -y -42 = (y+6)(y-7) when factored
Y= 6/7x +6
44