Answer:
step by step Step-by-step explanation:
Simplify (2-5a) (5-7a)
using BODMAS, we'll open the bracket
2(5-7a) -5a(5-7a)=0
(now, we'll multiply what's outside with what is inside the bracket)
10-14a-25a+35a² =0
now we simplify (-14a-25a), which will give us
10-39a+35a²
proof,
10-14a-25a+35a²
2(5-7a) -5a(5-7a)
(2-5a) (5-7a)
2-5a= 0 , 5-7a= 0
(let the numbers without the letters cross over to the other side of the equal '=' sign, i.e,)
(whenever a '+' or a '-' sign crosses the equals '=' sign, it changes to the opposite sign, e.g +2 changes to -2, or -2 changes to +2 after crossing the equals sign)
-5a= -2 , 7a= -5
(now, divide through by the number carrying the letter, i.e)
-5a -2 - 7a -5
—— = —— ,. —— = ——
-5 -5 -7 -7
(now we truncate '-' sign with '-' sign and similar number with similar number, which now gives us,)
a = 2 ,. a = 5
— —
5 7