# How do you factor 2a^4+21a^3+49a^2?

${a}^{2} \left(a + 7\right) \left(2 a + 7\right)$
$2 {a}^{4} + 21 {a}^{3} + 49 {a}^{2}$
=${a}^{2} \left(2 {a}^{2} + 21 a + 49\right)$
=${a}^{2} \left(2 {a}^{2} + 14 a + 7 a + 49\right)$
=${a}^{2} \left[2 a \left(a + 7\right) + 7 \left(a + 7\right)\right]$
=${a}^{2} \left(a + 7\right) \left(2 a + 7\right)$