Mi madre ha comprado 8 decenas y cinco unidades de latas de tomate a \( \$ 0,75 \) cada una; 4 centenas y media de latas de conservas a \( \$ 0,5 \) cada una y 12 cartones de leche a \( \$ 0,25 \) cada uno. ¿Cuánto ha pagado por la compra?

4. Simplify: \( \frac{3}{8} \div\left(\frac{3}{8}-\frac{1}{4}\right) \div \frac{7}{3} \)

1) Calcula y representa las curvas de nivel de la función \( f(x, y)=x^{2}+(y-1)^{2} \) \( c=-1,0,1 \)

3. A contractor is helping a client narrow some choices on a home remodel. The contractor wants to present 3 layout options out of 5 possibilities, 2 roof materials out of 6 possibilities, and 4 front door options out of 8 possibilities. How many different layout+roof + front door choices will the contractor present to the client?

The function \( g \) is defined below. \[ g(x)=\frac{x-7}{x^{2}-13 x+42} \] Find all values of \( x \) that are NOT in the domain of \( g \). If there is more than one value, separate them with commas.

2. Calcular el area de un terreno triangular cuyos lados miden \( a=9 \mathrm{~m} \), \( b=15 \mathrm{~m} \) y \( \mathrm{c}=12 \mathrm{~m} \).