5(9-30a+25a^2)-5(9a^2-49)=45-150a+125a^2-45a^2+245=80a^2-150a+290
(0.2×3)2 = (2×0.2) × (3×2) = 0.4×6
1)α-β=102⁰;⇒α=102⁰+β;
α+β=180⁰⇒102⁰+β+β=180⁰⇒102⁰+2β=180⁰
2β=180⁰-102⁰=78⁰;
β=78⁰/2=39⁰; α=102⁰+39⁰=141⁰;
2)180⁰-124⁰=56⁰
Там умножение?
если умножение то 58×23=1334