Question

Which one (a, b, c or d) is not true if x-5y=7

Answer 1

`\large\boxed{B.\ y=(x-7)/(-5)}`

Explanation:

`x-5y=7\qquad\text{add 5y to both sides}\\\\x-5y+5y=5y+7\\\\x=5y+7\to\boxed{A}\\------------\\x-5y=7\qquad\text{subtract x from both sides}\\\\-5y=-x+7\qquad\text{divide bothg sides by (-5)}\\\\y=(-x+7)/(-5)\\\\y=(x-7)/(5)\to\boxed{\text{it's not equal to expression in B.}}\\------------`

`C.\ 4x+2y+7=5x-3y\qquad\text{subtract}\ 4x\ \text{and}\ 2y\ \text{from both sides}\\\\7=x-5y\to \boxed{OK}\\----------\\D.\ 3x+10y=4x+5y-7\qquad\text{subtract}\ 4x\ \text{and}\ 5y\ \text{from both sides}\\\\-x+5y=-7\qquad\text{change the signs}\\\\x-5y=7\to\boxed{OK}`

Answer 2

Explanation:

answer : B

y = (x-7)/-5

-5y = x -7

x +5y = 7 no x-5y=7