$a)x^2-xdlax=7$

$7^2-7=49-7=42$

$b)a^2-3a+1dlaa=-4$

${\left(-4\right)}^2-3\cdot \left(-4\right)+1=16+12+1=29$ ${\left(-4\right)}^2-3\cdot \left(-4\right)+1=16+12+1=29$

$c)1+x\left(x+4\right)dlax=-11$

$1+\left(-11\right)\cdot \left(-11+4\right)=1+\left(-11\right)\cdot \left(-7\right)=1+77=78$

$d)x-2ydlax=1iy=-1$   

$1-2\cdot \left(-1\right)=1+2=3$

$e)2x^2-y\left(x+1\right)dlax=-2iy=5$

$2\cdot {\left(-2\right)}^2-5\cdot \left(-2+1\right)=2\cdot 4-5\cdot \left(-1\right)=8+5=13$

$f)\left(m+1\right)\left(n-2\right)dlam=2in=1$

$\left(2+1\right)\cdot \left(1-2\right)=3\cdot \left(-1\right)=-3$