Evaluate the expression 7a² - 3b³ when a) a= 4, b= -2 b) a= -8, b=5 You will end up with 2 answers here, substitute and solve.

Answer

Step-by-step explanation:

7a²-3b²

Replace a=4, b=2

7*4²-3*2²

= 112-12

= 100 first answer

7a²-3b²

Replace a=8, b=5

7*8²-3*5²

448-75

= 373 second answer

u = -(6/7)w

step-by-step explanation:

place all values with 'u' on one side of the equation.

4u + 8w = - 3u + 2w

4u + 3u = 2w - 8w

further simplify the equation by solving the addition and subtraction.

7u = - 6w

make 'u' the independent variable by placing its co-efficient on the right-hand side.

u = - (6/7)w