Linear functions SAT question

Choice A is correct. An equation defining a linear function can be written in the form $h(x)=ax+b$, where $a$ and $b$ are constants. It’s given that $h(0)=41$. Substituting $0$ for $x$ and $41$ for $h(x)$ in the equation $h(x)=ax+b$ yields $41=a(0)+b$, or $b=41$. Substituting $41$ for $b$ in the equation $h(x)=ax+b$ yields $h(x)=ax+41$. It’s also given that $h(1)=40$. Substituting $1$ for $x$ and $40$ for $h(x)$ in the equation $h(x)=ax+41$ yields $40=a(1)+41$, or $40=a+41$. Subtracting $41$ from the left- and right-hand sides of this equation yields $-1=a$. Substituting $-1$ for $a$ in the equation $h(x)=ax+41$ yields $h(x)=-1x+41$, or $h(x)=-x+41$.

Choice B is incorrect. Substituting $0$ for $x$ and $41$ for $h(x)$ in this equation yields $41=-0$, which isn't a true statement.

Choice C is incorrect. Substituting $0$ for $x$ and $41$ for $h(x)$ in this equation yields $41=-41(0)$, or $41=0$, which isn't a true statement.

Choice D is incorrect. Substituting $41$ for $h(x)$ in this equation yields $41=-41$, which isn't a true statement.