So x + y = 45, and 4x + 5y = 195. Get y by itself. Subtract x from both sides in the first equation to get y = 45 -x, and subtract 4x from the second equation to get 5y = 195 - 4x. Divide by 5 to both sides to get y = 39 - 4/5x. 39 - 4/5x = 45 - x. Add x to both sides to get 39 - 1/5x = 45. Subtract 39 from both sides to get -1/5x = 6. Divide by -1/5 to get x = -30, or 30. In the first equation, do 30 + y = 45. Subtract 30 from both sides to get y = 15. Check. 4(30) + 15(5) = 195, or 120 + 75 = 195.
Answer:
b. only reason is correct
2.05 kg=2.05 ×1000 g
=2050 g
so the Assertion is incorrect
Find slope
slope betwen 2 points (x1,y1) and (x2,y2) is (y2-y1)/(x2-x1)
so
first make denoms same
denom is 10
(4/5,1/5) turns to (8/10,2/10)
(1/2,3/2) turns to (5/10,15/10)
slope=(15/10-2/10)/(5/10-8/10)=(13/10)/(-3/10)=13/-3=-13/3
use point slope
use (4/5,1/5)
y-y1=m(x-x1)
a point is (x1,y1) and slope is m
y-1/5=-13/3(x-4/5)
expand
wait, we don't need to do that, the only one with slope -13/3 is D
answer is D
