Y^2 - y - (y^2 - 10y + 25) = 2
y^2 - y - y^2 + 10y - 25 = 2
9y - 25 = 2
9y = 27
y = 3
1) (x³ + 3x²) + (3x + 9) = x²(x + 3) + 3(x + 3) = (x² + 3)(x + 3)
2) x² + xy + 2x + 2y = (x² + 2x) + (xy + 2y) = x(x + 2) + y(x + 2) = (x + y)(x + 2)
3) m² + mn - 5m - 5n = (m² - 5m) + (mn - 5n) = m(m - 5) + n(m - 5) = (m + n)(m - 5)
4) a² - ab - 3a + 3b = (a² - 3a) + (-ab + 3b) = a(a - 3) - b(a - 3) = (a - b)(a - 3)
5) (10ay - 5by) + (2ax - bx) = 5y(2a - b) + x(2a - b) = (5y + x)(2a - b)
= (2a)³+(3b)³=8a³+27b³=8*8+27*1=64+27=91
(sina+cosa)/√2=√2/2*sina+√2/2cosa=sin45sina+cos45cosa=cos(45-a)=cos(a-45)