You are given the following linear programming model and Excel spreadsheet to solve this

problem:

MAX:

$25$ X$1+35$ X$2$

Subject to:

Constraint $1$: $6$ X$1+4$ X$2<=1500$

Constraint $2$: $4$ X$1+8$ X$2<=2700$

Constraint $3$: X$2<=800$

X$1,$ X$2>=0$

X$1$

X$2$

Number to

make:

Unit profit:

Objective

$25$

$35$

$10$

Constraints:

Constraint $1$

Constraint $2$

Constraint $3$

LHS

RHS

$1500$

$2700$

$800$

What formula should be entered in cell D$8$ in the accompanying Excel spreadsheet to compute the LHS of constraint $1?$ Choose a formula that can subsequently be copied from the cell D$8$ and pasted to cells D$9$ and D$10?$