Answer:
Step-by-step explanation:
No idea
4(x² - 2) = 28
1. Distribute the 4
4x² - 8 = -28
2. Plug in 3 and -3
4(3)² - 8 = 28
4(-3)² - 8 = 28
3. Square 3 and -3
4(9) - 8 = 28
4(9) - 8 = 28
28 = 28
The reason both answers are the same is because whenever you put a negative number to an even power, the result becomes positive because any negative multiplied by a negative number is always positive.
28 = 28
Fist plug in 7 in to the X values like so 12 (3 (7) +5 (7)) then solve in side the parenthesis 3×7 =21 and 5×7=35 then add them 35+21=56 and then you are left with 12(56) or 12×56= 672
0.4% of 100 is .4 whoops i thought it was 0.4 as a decimal :P
Answer:

Step-by-step explanation:
2x + 5y = 6 --------( 1 )
5x - 2y = 9 --------( 2 )
_____________
( 1 ) x 5 => 10x + 25y = 30 -----------( 3 )
( 2 ) x 2 => 10x - 4y = 18 ----------- ( 4 )
______________
( 3 ) - ( 4 ) => 0 + 29y = 12

Substitute y in ( 1 ) =>
