you need 10 8' planks of wood because 15x3= 45+9x4= 77, then 77÷8= 9.625, but you can't get .625 of a plank, so 10. hope you get a good grade!
Answer:-25+-12
Step-by-step explanation:so I made x value as 5 so I multiplied -5x5 and it's -25 then I multiplied -4x-7 and that's -12 so the equivalent expression for my way is -25+-12