tolong dijawab secepatnya ! pr soalnya

a. 20y - 10)
b. 5x^2 + 24x - 5
c. -4x^2 + 14x - 49

Jawab =
a. 10*(2y-10) = 20y - 100

b. ( x+5)*(5x - 1) = {(x+5)*5x} + {(x+5)*-1}
= (5x^+25x) + (-x -5)
= 5x^ + 25x - x - 5
= 5x^ + 24x - 5

c. (7-2x)*(2x-7) = {(7-2x)*2x) *2x} + {(7-2x)*-1}
= (14x - 4x^) + (-7 + 2x)
= 14x - 4x^ - 7 + 2x
= -4x^ + 14x + 2x -7
= -4x^ + 16x - 7

cat :
^ = pangkat dua / kuadrat

Semoga membantu :)